The Electronic Control Module (ECM) is a central control hub for a vehicle’s engine, managing essential functions such as the Check Engine Light. It typically lasts the vehicle’s lifetime but can fail before the entire vehicle does. Common indicators that suggest an ECM failure include poor engine performance, unusual fuel consumption, and difficulty starting the engine.
To diagnose a failing ECM early, it is important to avoid getting stuck by the side of the car, as the check engine light may be on. If one module cannot communicate with the ECU, it will set a diagnostic trouble code and turn on the check engine light. The computer will also turn on the check engine light itself if it has.
When the alternator diode pack fails, it can leak AC voltage, causing disruptions in the electrical system. The radio, lights, and power windows have a separate circuit on the fuse box and would not be routed through the ECU. Some common issues with an ECM include the head unit stopping turning on, interior lights not working, power windows, locks, and key chime not working, internal lights/locking going mad while driving, and lights coming on when the car is switched off and stationary.
Replacement of the COURTESY fuse is recommended to protect not only the courtesy lights but also the BCM circuits that control things like power locks. Additionally, replacing all lights with LEDs can cause all lights to not come on.
In summary, recognizing the signs of a failing ECM early can save you from costly repairs and potential breakdowns. By replacing the courtesy fuse and ensuring proper communication with the ECU, you can prevent these issues and ensure your vehicle’s safety.
📹 How To Diagnose A Faulty ECU With No Communication
No start of the vehicle and no direct communications to the engine management system – ECU fault right? Or could it be …
What happens to a car if the ECU fails?
The Check Engine Light (CEL) is a common indicator of an ECU issue, which can be triggered by various problems within the engine or its systems. Common causes of ECU problems include engine misfires, reduced fuel efficiency, stalling or rough idling, sudden power loss, and transmission issues. Understanding the root causes of ECU problems is crucial for diagnosing and addressing them effectively. Common causes include sensor malfunctions, wiring problems, software glitches, electrical issues, water damage, and improper modifications.
Sensor malfunctions can result from faulty sensors, such as oxygen sensors, crankshaft position sensors, or mass airflow sensors. Wiring problems can disrupt communication between the ECU and various vehicle sensors. Software glitches can affect performance, while electrical issues can cause malfunctions. Water damage can damage the ECU and cause erratic behavior. Improper modifications, such as performance chips, can interfere with the ECU’s normal operations if not installed correctly.
What causes interior lights to stop working?
Car interior lights, including door and dashboard lights, can malfunction due to various reasons, such as blown fuses, wiring issues, or burned-out bulbs. Peninsula Auto Clinic in Northern Beaches offers car repair services to ensure the lights are functioning correctly. To fix the issue, rotate the dimmer, replace a blown fuse if one light doesn’t work with the others, repair a short circuit if the fuse and wiring are faulty, replace the door jamb switch if the door lights don’t work, and replace the burned-out bulbs. The mechanic team at Peninsula Auto Clinic is dedicated to ensuring the safety and functionality of your vehicle.
What’s the symptoms of a bad ECU?
ECU malfunctions may result in erratic shifting patterns in vehicles with automatic transmissions, which could manifest as harsh or delayed gear shifts. Furthermore, problems with the engine ignition system, such as misfires or engine performance issues, may also arise.
Does the ECU control the lights?
An Electronic Control Unit (ECU) is a crucial device that manages a vehicle’s electronic features, including fuel injection, temperature control, airflow adjustment, and sensor lights. It stores base numbers and metrics in its memory and uses data from various sensors to optimize the output of the electronic systems. The ECU receives input from various parts of the vehicle, such as airbag on/off indicators, change lane assist, and door lock ECUs. For example, an airbag on/off indicator would receive input from sensors that detect seat positions, while an ECU for change lane assist would receive input from forward-facing radar systems.
Will lights turn on if the alternator is bad?
The presence of dim or flickering lights, or a lack of illumination altogether, is indicative of an alternator that is nearing the end of its operational lifespan. Such symptoms may manifest in various lighting systems, including dashboard, instrument panel, headlight, and other exterior lighting. The alternator is responsible for providing the electrical power necessary for the operation of the vehicle’s lighting system. If the alternator is not functioning optimally, the lighting may exhibit reduced luminosity or may become entirely inoperable.
What does it mean when the car won’t start but the lights come on?
A dead battery in a gasoline or diesel-powered car can be identified by several signs. If the engine doesn’t turn over, the standard 12-volt battery might be the culprit. Other signs include the radio not turning on or the check-engine light flashing but not staying on. Low battery levels can also be seen in doors failing to open with a remote or a lack of lights when turning the key in the ignition. If the car starts slowly and dies immediately, the 12-volt battery is likely dead or dying.
To test this theory, jump-start the car and see if the engine turns over. If the starter fails, the likely problem could be the starter, a small electric motor powered by the battery. Some signs of a bad starter include lights being on but the engine not cranking. It’s crucial to replace the battery immediately.
Why won’t my interior lights turn on in my car?
When all car interior lights stop working simultaneously but other lights like the radio still work, it suggests a common issue with blown car fuses and fusible links. The fuse box may be located near the glove box, under the dashboard, or in the engine compartment. If your car has multiple fuse boxes, your owner’s manual can be helpful in locating the right one. If you cannot find the fuse, search the internet for a picture of the exact fuse box.
The “lights” fuse is usually the issue, but it can vary from vehicle to vehicle. To determine if a fuse is blown, use a multimeter or test light. If a multimeter shows no continuity between the terminals of a fuse, it indicates that it is blown. If you can’t find a wiring diagram for your specific make, model, and year, checking all fuses labeled “lights” is usually sufficient.
When your car won’t start but all the lights come on automatically?
A dead battery can cause issues with electronic devices, such as headlights, radios, and other car electronics, as they draw minimal amperage. Engine starters can pull up to 300 amps at once, which is too much power for a battery with a low charge. If the battery tests low or fails a load test, it must be charged. The problem can be solved by accepting a charge or jumping from another battery and starting the vehicle. If the vehicle doesn’t start, it may be a blown fuse, broken ignition switch, or a bad starter.
To check the fuse, check for a blown fuse or fusible link, and inspect the fuse box for a metal wire. If the wire is severed or damaged, a blown fuse may be preventing power from reaching the starter relay or solenoid.
Why is my car not starting interior lights flashing?
In the event that a vehicle’s engine fails to start and the dashboard lights begin to flicker, it is probable that the battery is not sufficiently charged to facilitate the starting process. In the event that the battery is not functioning as it should, it would be advisable to replace it. Other potential causes include a malfunctioning battery due to a failed alternator, contaminated or lax battery cables, a defective ignition switch, or faulty control modules.
Why do my interior lights stay on when car is off?
In the event that the interior lighting of your vehicle fails to extinguish, it is recommended that you inspect the switch for any irregularities that may have been caused by individuals such as passengers, valets, or car wash employees. In the event that the switch is in either the “door” or “off” position and the light persists in remaining illuminated, it is advisable to seek the expertise of a qualified mechanic.
What controls the light inside the car?
Interior car lights are controlled using switches, sensors, or other controls and are usually powered by the car’s batteries or electrical system. There are three categories of car interior lights: displays and indicators, accent lighting, and illumination. Dome lights, mounted in the center of the car’s ceiling, illuminate the interior of a vehicle and are activated when opening or closing the door or turning off the ignition. They perform different functions within an automobile’s ecosystem.
📹 SYMPTOMS OF A BAD ECM (ENGINE CONTROL MODULE)
In this video, you will learn 4 symptoms of a bad or failing engine control module. Watching this video will help you diagnose to …
Great article and explanation. I tested my EUC that came with a swap kit for “crank but no start” with your information. After verifying all good grounds, constant 12v, and switched 12v, my EUC failed to pull the constant 12v to ground, allowing the relay to receive a negative signal and switch the relay on and provide power to the other side for boot up.
Great article I learned a considerable amount from perusal this one article (now subscribed) I have a Maxicue OBD reader and it has thrown up this fault Audi A3 (8P) Convenience system (TP) 01320 intermittent Climate control no communication 00352 intermittent terminal 30a open circuit 0095 intermittent Key 1; adaption limit exceeded Faulty or no basic setting/adaption 01565 Permanent Luggage space lighting Short circuit to ground > The 01565 may now shed some light (sorry about the pun) about the parasitic drain that I could not find. But anyway the car is still driveable. I look forward to your response Tony
Hi guys, very informative article thanks 😊. I have an intermittent no crank on a A4 B8 CAGA TDI. When the car won’t start, the main relay (T30) goes bonkers, clicking in and out. Pin 86 and 30 have constant battery voltage when the T30 relay is doing this clicking, pin 85 (ground switch from ecu) has battery voltage until ignition on and then has 1.04v…. I’ve been over and over the wiring and I can’t find any issue. My question is: Should pin 85 drop to 0v as its ground switched by the ECU? This A4 only drops to 1.04v and there perfect continuity on th8s very short wire from pin 85 to ECU, no voltage drop on that wire either. Would very much appreciate a response from your experience 👍
Have a suzuki xl7 that runs great when it’s cold but once it been running. That’s when I have issues. The speedometer sometimes works,the thermostat started running hot. The engine isn’t hot at all. No leaks in the radiator. The engine light has come on, now it doesn’t come on. The traction control light came on. Now it doesn’t. It shifts hard,slipping, Complete stop then shift hards when going to complete stop. Sometimes it doesn’t want to go into gear. Drives great when its cold. Any suggestions?
Hi Tim, i have a ford S max that wont let me clear codes and is limiting power while driiving like 2200rpm and then nothing turbo working drives fine unless you put your foot down and its like its in limp home mode but i can get on the motorway and do 80mph just takes forever. any ideas ? 2008 2.0 tdci titanium. its like its bricked when you lock your mobile with the wrong code in it, turns up but its not doing much. how do i find which version of ECU i have to get 1 from you or send mine back to check it.
My Ford Territory had ECM problems. Had it replaced numerous times. Now the front right brake locks up the wheel. Had the vehicle towed back to the workshop. After 4 weeks in the workshop I still have not been contacted yet. I told them I don’t want the car back unless they can guarantee me that the car is Safe to drive. Will probably NEVER get the car back… (NOT HAPPY)
Hi I have a Mondeo 2.0 Zetec petrol. It is showing a p0607 code and a P2110 code which is reported to be a common problem with this model either being the ECU or the throttle body. My throttle body appears to be ok . Could it be any other sensors causing this issue or Will it be the ecu the car goes into engine malfuction immediately the ignition is switched on even though engine is not running when engine running it mifires, Any help would be appreciated . Thank You.
our nissan juke has undergone a engine rebuild process due to excessive oil usage. the garage is now telling us the engine has been rebuilt but they cannot test drive vehicle because there is a definite problem with the ecu unit and want to send it off to a specialist for diagnosis, at a cost to ourselves. what will this test tell us and do you think we are being fobbed off. so far works have cost us 3500 pounds on our 66 plate juke with 30 thousand miles on clock. please help. yours truly shaun
Hi I’m working on a 2008 Nissan Armada, and I’m not getting a reading from my obd 2,also my indicator light for the gear is not lit up, there’s no service engine light displaying. I can’t self test the system and I hear clicking sounds in the rear of the truck. Please please help me out with this project if you would sir thank you In advance
2004 Toyota RAV4 – crank no start issue: hi, I have a 2004 Toyota RAV4 and it would not start on its original ECU, note when the ignition is turned on the battery charging light indictor does not come on and also the engine check light is not coming on. i replaced the ECU with another one that came in from New Zealand and after fixing the broken wires on the deceleration Sensor the car started once and died after 30 seconds. after that even the replaced ECU stopped showing the Engine check light and the battery charging light when the ignition is turned on and it would not start. when i scanned the car with a LAUNCH scanner, the ECU is accessible. It only shows the ABS and SRS scan results. What could be the problem. Does the 2004 RAV4 have CAN system on the car? note the only wires on the OBD2 connector are on Pins 4,7,9,12,13, 15 and 16.
I`m trying to create a waveform to test a smart alternator. Mitsubishi. I`ve heard the frequency is 90 hertz on a Ford Focus and duty cycle shout be around 37 to 45 percent. I can not find any information anywhere. This is off a Subaru Impreza. I`ll start off using 5 volt square waves and see how I get on.
anyone can tell on E46, How many places we can isolate the BUS.(s) the car sometimes has mind of its own. sometimes windows dont work, sometimes ac, or sometimes wiper works own its own. or no indicator sometimes. his is after heavy rain. but the convertible was never driven on water. any input can help thanks.
Monka 1600 low mileage Drove parked then 2hrs later no crank no error code, Had RAC out problem with ECU 5amp fault. might be a broken lead due to the very hot weather, towed to Vauxhall for diagnostics. Got to wait till October. Told it will be expensive, could it be the ignition, we had this changed about 3/4 years ago by a different garage.
I don’t know if you are still around but if so my problem is with a 2008 Saturn Aura XR 3.6 L . RPMs Idels great but as soon as you touch the accelerator the RPMs jump to over 3000 rpm and an alert comes on the dash traction control and ECU needs service and then that goes off with ECU off came on then went off. could this be a bad ECU????? Changed out the Throttle body with a new one. That’s when the problem started with the idle racing., you thought I’m totally confused.
Hello please I need your help I was driving my 09 Honda accord the other day it as never giving me any ecu related code before the car just dead on me o was told is the ecu so we get another used keihin ecu we even test it on another 09 Honda and it works perfectly but when we put it in my car same thing it didn’t start and is not communicating with scanner any help please
I dear sir, in my car have loss acceleration and when i give acceleration there is voice and car jerking, i changed plugs, coils, camsensor but still i’m getting error p0344 in honda civic 2017 please help me I’m suffering by the way i changed the battery before it was 5amp now 4.5 amp is it battery issue or ecm? Because my car start good if there is battery it will not start good right?
Hi, I have a Volvo V50 that has problem with anti-skid, the faultcode is ABS-0101, I can switch the car on and off a few times and the fault is no longer present until the engine dtops and is restarted, then the samething is back Our M.O.T. does not like this at all 😢 Do you have any leads where to begin a search? Sinc. Paul
Yeah I have a 1988 Chevrolet Cavalier Z24 5spd and digital dash! It smells of gas at idle also idles like it’s missing, it wants to haul ass then very early it loses it’s powerband, I changed the O2, I changed as far down to the ignition control module, tb cleaner up the wazoo flushed changed fluids, but still runs like Shit! This is my question. Is this my engine computer???
Hello I came across this article and I am having same kind of issue car cranks but does not start-no spark no pump noice running, on dashboard all lights comes on and off but I don’t have check engine light on off at all plz help 1997 Toyota Supra Japan version Jdm 2jzgte automatic Caused Parked for 6 months and boost up to start and than turned off than crank it was low battery voltage and it cranked and than click sound it never start checked fuse box but can’t get to fire all I know I am missing engine on dash sign in starting when ignition switch on
Hi hondajazz green key flashing car crank no start it look immobiliser no spark no fuel.locksmiths check key it’s ok immobiliser ok but no start.put break out bar good grd sig good chassis grd.but can low n can high both reading are high I can’t get all together 5v. Unplugged ecu look for can low n can high got big reading with multimeter.yr advice please. Thx
Hi there. Good article I have a delphi mt05.3 ecu. And when I start my engine with engine light on it starts and dies I have had engine out 5 times and all is good new wire harness and still the same issue 😢 is it the ecu I am thinking of buying a new ecu witch is 160£ but I can get a same ecu but been told it needs matching up with my engine 😮 I don’t no wot to do. It is also a efi scooter 125cc 2021
Thanks a lot, I have had a problem the car was start first thing in the morning then would have a check engine light on then after the car has been stopped and started for 3 or 4 times the check engine light would disappear I then in my wisdom decided to use electrical contact cleaner made sure it was dry with the airline plug them back in and now. Now I have a Christmas tree and the car is running rough how long will you need to fix and how much
2009 grand marquis. 44k miles. ABS traction control and parking brake red light went on while driving on highway in rain. Light came on after bump in road. Lights on steady since. Was able to pull a U1900 code with blue driver dongle scan. Missing CAN message from hec. The car runs and drives fine. Speedometer working ok. Cruise control ok. Transmission shifts fine. All readiness monitors ok. Can not communicate through ALDL with Autel maxisys. No communication with PCM, ABS, or dash cluster (gateway module). I am able to communicate with LCM DCM RCM modules. Measured 63 ohms on termination resistance at ALDL and got 12 volts at pin 16 and both grounds at pins 4 and 5 seam ok. Any thoughts would be appreciated. Thanks.
Hi, my BMW F36 wont start or crank. ISTA shows no communication with DDE ECU. Tested Relay and all fuses all good, there is 12v at the relevant pins on the ECU connector and Grounds to chassis 0ohms. Particular fault that catches my eye is (Wake Up line to the intelligent battery sensor short circuit to B+ or disconnected), Any advice appreiciated
On Hyundai santafe 2014,My check engine light doesn’t come up at all. It doesn’t accelerate when I climb a hill even when the acceleration pedal is completely pressed and the engine does not go off. The fuel consumption is quite enormous as if the fuel is leaking. After diagonising, I have a P0365 (Exaust camshaft position sensor(CMP) B circuit fault (Bank 1). The sensor was checked okay. Even changed. After troubleshooting, it was concluded to change the ECU. What do you suggest?
thanks for this educative article, my automatic transmission has been slipping while driving in 2nd and 3rd, my mechanic scanned the problem with a diagnostic computer and he said there’s no communication between the ECM and TCM, he has advised that I replace the ECM. Can a faulty ECM also cause transmission problems?
I have a 2002 Volkswagen Golf the only way it will start is to turn the key with the battery disconnected turn the key on to ignition hook the battery back up get back in the car and continue starting the car at the car will start and die instantly turn it off turn it back on mobilizer light goes out car won’t start just cranks and that’s the only way it’ll start is if you print the key on with the battery just connected and then connect the battery up with the key on and then start it at the whole time that that’s going on the immobilizer lights flashing
Hi boss I gaved my a class mercedes a180 2014 petrol manual engine for mercedes service stratford for engine light was coming on because of misfire engine on slow speed some was jerking or something hiccups now the mercedes technicians keeping for 20 months couldn’t fix it first they said to me because of bad wiring doing misfiring next week they said engine control s problem after 2 months they saying ECU problem and they still keeping my vehicle with them I don’t know what to do please you hot some way to tell me please thanks I already subscribed your website thanks ??
I have a 2012 Honda Civic si sedan. I was driving home one day and it just turned off. I plugged my code reader and it shows up as linking error. I’ve changed relays to new ones. Fuses to new ones. I have power going to all sensors and fuel pump. but none going to injectors and ignition. My code reader is not communicating to ecu. Nor does the ecu communicate with the car. I need help. I’m losing my mind.
I own a 02 nissan x trail when pushing down on the gas pedal check engine light comes on.and then she losses power can it be the ECU.i’ve change fuel pump throthle body MAF sensor clean out the cat camshaft crankshaft sparkplugs ignition coil 😂only thing left is the ECU.r should i just swope the engine and call it that?
hi this paul with a 2008 vw touareg ecu problem. when . if i pull battery + or – for a while my engine runs normally. after switch off and turn on again i have no check light and wont start unless i remove positive or negative on battery . what could be the prob? article was clear thk you also for that
Sir, I have a question. Is there a single pin, or a couple of pins that “turn on” the voltage regulator to get it (the alternator) to produce power? I’m dealing with a GM CS AD series alternator. I don’t have need of anything else other than trying to get the alternator to produce power. ANY help you can give would be appreciated. Thank you.
I’m not getting a single on my o2 sencer I change both sencers and ther not reding no no signal ther was a short on the whire both sencer I fix them and the scanner not reading nothing on the sencer both sencer can it short out the ecm ther is no signal at all I reset the o2 sencer and no light is on yet so is it the ecm
Hi got citroen dispatch 2.0hdi start problem in morning U1118 Communications On The Comfort CAN. No Communication With The Built-in Systems Interface Permanent Fault P1693 Remotely Controlled ECU Wake-up. Start Or Stop Requests Missing Or Invalid Permanent Fault U2001 Remotely Controlled ECU Wake-up. Main Wake-up Request Missing Or Invalid Permanent Fault Live Data Qty Airbag
Great article. I have a problem. 2013 Tacoma 2.7L, I don’t think this is relevant but lightning struck near the vehicle during a storm, truck started the next morning and while driving to town just shut down. No check engine light, cranks but no start, no communication, only with airbag. checked 5volt reference, 2.8 volts at mass air which I thought was not pulling down enough to be a grounded sensor but started disconnecting sensors anyway. of course all disconnected voltage came up to 3 volts but did not return to 5. Is the 2.8 volts at THA wire on maf to high to be a grounded circuit or sensor? Also can bus looks hashed.
Great info, thank you! – I have a question – can a car be wired up to only work with a specific ECU? – My car (golf 2.0 8V) is in at the auto as we speak – it went in with a 2.0 polocub – but he said it has no spark…the way it was previously wired, meant they took a spark from the one loom, and tapped in creating a separate one (yes i had 2, lol ) -and yes it was starting up before it went in – i was just wondering if he tried to up-sell me. Or Could the previous wiring be wired up to “borrow a spark” ? or cause it to “blow” an ECU? – He sold me a 1.8 ECU…for my 2.0 engine, should i be worried? lol, Thank you
2010 Chev HHR, I was programming remotes wth Autel AP 200 programmer, software on an ipad. Ipad shut down while trying to communicate with the vehicle. Chime went off, door locks cycled, gauge needles cycled, everything went dead. Any insight into what has been damaged? Needs to be replaced? Thanks in advance
Great article! These are the steps I need to perform on my Z3. After receiving a cloned DME, car cranks but no start, I still not sure where the DME relay is on my vehicle since it’s at different locales between M43 and M44 engine. I have the M44. I have the right wiring diagram. Any advice is greatly appreciated, Thank you!
I have a question on 2004 suzuki that cranks but not start, and no comm issue and but have proper ground and power on pins 4,6, and 16 on the DLC . Also ECU is not grounding the control wire on the fuel pum relay control wire, therefore no power on fuel pump. However, I noticed igintion fuse that power fuel pump also powers the ecu and the spark plugs, that wire if I cut it from the fuse now the cut wire stilled attached to ecu shows ground. with a light test This supposed to be power but shows ground when disconned from the fuse does this mean there is a short in the ECU? Also the ECU is not grounding the control wire for fuel pump relay as I said. Would you say the ECU is shorted? Thanks
Hi I have a 2007 Ford Fusion. When I first got it the people I was told that it would not start. Ok the next day I checked out the connector and I got it to start. They also put a different engine same size. Anyway it would run so I’m just checking other stuff out and she just stop running. So I scanned it and came up withU0100 and now no start . No communication from PCs / or ecm to tmc.anyone everyone plz help me Resolve this matter please thank y’all
Hello. Your article was quite informative. We have tried to remap a van and took a reading via Flex machine however now after performing a writing we can’t start the car and no communication is present with ECU via diagnostic equipment or the Kess V2 machine (our other diagnostic machine). We have even tried to write original reading file via flex and still won’t start. Have you ever come across this?
First thing.. thanks by share this valuable information; In another hand…I have facing an issue with a Land Rover ECU, during they scanning process is not recognized…I already checked: 1).- CAN Bus lines and they are working well. 2).- ECU voltage and ground feed are fine. They question is….could ECU lost “his” identification” after a short circuit ocurred during the engine replacement??? Your advice is well appreciated.
I failed emissions due to no communication to ecm. The data is cleared out every time when car is turned off. No warning lights are on like the the check engine. They just can’t get any data readings. I have a fiat 500 turbo 2013. one suggested it might be the f-18 fuse. when I looked it up it says power train. any thoughts? electrical or ECM issue
Hi We have tried to remap a Mercedes C220 2013 and took a reading Kess3 OBD tool however now after performing a writing we can’t start the car and no communication is present with ECU via diagnostic equipment or the Kess 3 machine (our other diagnostic machine). can you please guide why is ecu or any other obd reading machine detect ecu, we have checked all the fuses all are ok. can we check relays or change relay. please guide we shell be very thankful to. if we do bench read and write what do you think.
Wow what a really great an informative article. I have a question. I recently just put a rebuilt VR6 in my Volkswagen. Ive had a crank no start/ no spark issue ever since and I haven’t even heard the engine run yet unfortunately. I connected the laptop with the VCDS and I have no communication with the ECU I checked all spark, fuel and Air lines and power and grounds everything is fully connected they all look good. I am getting high resistance at the fuel pump. I do not here the fuel pump turn on. Any ideas what it could be?
Thank you for perusal! OBD2 Scanner: amzn.to/3PHRplS Check out AllDatadiy repair manuals: gopjn.com/t/SENKTklLS01DSE1NS0lOQ0dKRk9LTw Use code AD10VA for 15% off one-year subscriptions for any US Order Check out my merch: easyautofix.creator-spring.com/ Have car-related questions? Check out JustAnswer! They have verified auto mechanics that are available as live help 24/7: justanswer.9pctbx.net/qnj74y Buy a new ECM here: advanceautoparts.rt8x.net/Ry9zGb Here are some of my favorite items that you might like: Tools: amzn.to/3xNDb8g Car Vacuum: amzn.to/3EjhPSJ Cleaning Tools: amzn.to/3El7dCG Water Repellency Wiper Blade: amzn.to/3utvK50 Cleaning Gel For Cars: amzn.to/36NIiMr Portable Air Pump for Car Tires: amzn.to/3uBuPzA Headlight Restoration Kit: amzn.to/3qDpOVH Amp Jump Starter: amzn.to/3pMd0vx
I have a 2013 F-150 and I have some of these same problems. I use a OBD2 code reader and it shows random problems at random times. One time it will show throttle body then the next time it will show O2 sensors and a couple of others. Again at random times. I have an extended warranty on this vehicle and take it to the dealership but they say they can find no codes.
Basically if you have a throttle performance problem linked to a bad computer, you could possibly just maybe experience shifting problems. The first thing to do is check power & ground, then check your communication wires. If a module isn’t out-putting the right voltage then it most likely has failed. It’s a good idea to run a wave pattern test on speed/timing sensors before replacing them. A lot of mechanics replace sensors without first checking their signal. Even more, mechanics that have been doing this for 40+years replace modules on a whim. Every module fails for different reasons, that’s why sometimes they’re hard to diagnose. 10 years mechanic here
Here is one for you: Lexus ES 300. Started to stall and idle was really weak. I took it to our regular shop and he changed the throttle body sensor. Was fine for a few weeks and started stalling again. Took it back and he cleaned out the throttle body of carbon build up. Worked fine for 2 weeks then started stalling again and it wouldn’t start. Took it to Lexus and they adjusted the throttle and said nothing else is wrong. Still having issues with starting and idle. Could the ECM be bad?
Simple and to the point. I think this is the problem I’m experiencing with my 2004 jeep. I heard that Jeep’s are bad about that. I’m driving and stall out. It’ll start back up, after a time but I’ve changed the TPS, the coil packs, the oil sending sensor and still my jeep dies, randomly! I’m so frustrated.
May I ask i have a 1996 chevy suburban 5.7 k 1500. Starts and runs like new unless its summer time. Turn it off to run in the store and come out and it won’t start until the next morning,fires right up then! The fuel pressure is perfect and it has a new distributor,plugs,wires,coolent temp sensor none of wich fixed this issue. NO check engine lights on! In the winter months this problem goes away. Thanks for the advice!?👍👍
I went through this with my 2011 Altima right before Christmas of 21. It took me a couple of weeks to make the educated guess that my ECM was bad. It kept throwing P0705 Shift Range sensor but I pur 2 new ones on it and didn’t fix it. I even did the multimeter pin test someone recommended on all 3 and they passed so after much research I got one from a place online (cheaper than going to Nissan) when I got it all installed the car wouldn’t run. I called them, they asked me to see if I can find out why it’s not running. I said way ahead of you, it’s not getting fire to the plugs. So they sent me a shipping label and asked me to send both of mine back so they could clone the original and flash theirs and send it back. When I got them back it worked. I never had another problem until yesterday. I went somewhere and when I went to go home, it’s in limp mode again just like last time. When I checked the code, same damn code P0705😡 I still had a new switch and just for aguement sake I tried it and just like last time, I think it screwed my ECM again. It’s only been a year and a half since I fixed this and about 4000 miles (my car only has 60 000 miles on it and I bought it new) at this point I’m ready to soak it in gasoline and burn it to the ground, I’m not gonna keep fixing the same problem at the ridiculous expense that frequently. Bought it brand new and these problems are getting ridiculous. I’ll NEVER own another Nissan again, I don’t give a damn if they paid me to take a truck load of them.
I haven’t yet replaced the ECM, my van 2013 Dodge Caravan starts and dies already. I’ve replace sparks, coils, rockers -lifters, and alternator I still get every code relating to misfires and slow response time in camshaft. I do have a used ECM I pulled from the yard. How would you tackle this? Tried clearing the codes with the scanner with no luck. Please any help would be so appreciated.
Now, i thought my 07 Ford Focus had an ECM problem. But it’s clear it doesn’t. Because my car runs and drive’s fine, but my cluster is lit up. The OBDII port doesn’t work, spedometer doesn’t work, all the light’s are on. But, the only three thing’s working on my instrument cluster are the gas level, seatbelt light, and highbeam light. Nothing else work’s. I looked at every single fuse in and outside. All are good. Tried to hook up OBDII reader and it wouldn’t connect. It started having this problem after last winter.
Wow. My starter went out and my alternator was acting up, replaced both of them had no codes prior, but my idol was choppy and my car was stalling. Finally get it started again and it’s throwing p2195 and p0500 codes but I reconnected everything and I checked to make sure my mas was connected. Everything looks good. Probably going to take it for a tune up play stupid and see what they tell me cuz I don’t want to mess with the electrics of my car and I’m not jumping to conclusions about my ECM being bad
This is describing almost exactly the problem I’m experiencing except for the shifting problems. Engine light code reads as an oxygen rich problem, but after switching out the ignition coils, spark plugs, both oxygen sensors, air filter, and also checking for air leaks…the problem persists. Then i remember getting a high pressure car wash, and water was leaking into the driver compartment. Thats when all the problems began with engine light, reduced power light, and traction control lighs all turning on….This is most likely the problem.
Excellent article,remember this, the newer your car is the more unlikely scenario that your ECM is bad unless it was in a flood or some catastrophe like that, a lot of ECM’s have capacitors in them and capacitors have a lifespan like everything else,some of these capacitors control or “help” the processors make decisions and if they are leaking their guts out (which they do as they age) then you start having problems,they start minor and get worse as they get older and leak some more, this usually happens 10\\15 years or so in the life of the car, less these days because the electronics are cheaply made. These problems need to be addressed promptly as the stuff they leak is corrosive to the board and what started as a simple problem will take out a nice chunk of the board overtime and cost you much more in the end,the only way to find out about this is to have a visual look at your ECM,you dont have to be a scientist or some super duper electronics specialist to conduct a visual inspection,it will be screaming at you as soon as you see it,sooooo if you have been replacing things you thought were bad and have checked and double checked everything and you still have issues more than likely its your board.
i had a turbo actuator fault.. mechanic reset light, next check engine light was gas pedal, replaced it and again light shortly after.. injector 3.. replaced it and another light just now came on.. truck runs fine just faulty lights i think.. volvo isx2350 in a 670 semi truck… could be computer issue.
I have all those symptoms except starting. However, I have one that you didnt talk about. One day all my dash warning lights came on all at once then they went back off, except for the engine light. Then I noticed, while on the freeway, that my speedometer was not working, and while I looked at it, it shot back up to where it should have been (about 70 at the time) could this also be ecm?
My car is 2015 Ford Fusion SE 2.5 L six speed automatic transmission. It’s sometimes will crank sometimes won’t. Also will die when I do start it. Could be ECM ? Weird thing is that only tire pressure fault light and steering wheel assist fault service required light will turn on. Also why do Auto Zone is able to read codes and OReillys doesn’t?
Hi I am a fan and watch your articles. I Do have a situation and hoping I get some direction. I have a question on 2004 suzuki that cranks but not start, and no comm issue and but have proper ground and power on pins 4,6, and 16 on the DLC . Also ECU is not grounding the control wire on the fuel pum relay control wire, therefore no power on fuel pump. However, I noticed igintion fuse that power fuel pump also powers the ecu and the spark plugs, that wire if I cut it from the fuse now the cut wire stilled attached to ecu shows ground. with a light test This supposed to be power but shows ground when disconned from the fuse does this mean there is a short in the ECU? Also the ECU is not grounding the control wire for fuel pump relay as I said. Would you say the ECU is shorted?
I got an 07 Camry, I recalled having it scanned for the check engine light and there was more then one codes that came back as problems. One of them was the ECM processor, the second code was an O2 Sensor. Last night I was driving home after a long day at work, when I was at least 5 minutes away from my home destination my exhaust became louder and my Rpm was stuck at 2,000rpm during idle at a stand still stop it drops down to 1,000rpm where it should be. My guess is it may be a bad throttle body or a bad ABS control module, the ABS light is also on. It’s a common problem on the 07-09 Camrys.
I got a 2017 Kia Forte LX from Drivetime. Seems it was sitting around too long. The car seemed so perfect. Ran great up until I took it off the lot officially.– I drove through a plaza slowly stepped on the gas and nothing, the car was off. The oil light, battery and check engine light came on. I was able to easily crank the car back up as if it never happened. Then it did it again 8min later. No codes showed up when the dealer looked at it. And he was just as confused lol smh. Do you think this is the fix it needs?
Hello,Circuit Intermittent, sometimes when you starter the vehicle check engine going on with VSA, nothing different after update, already replaced the crank shaft, the problem is still, I try to take off the cable from cam shaft sensor and I drive the car. It’s nothing gonna be happen no a check engine going on, the pcm has been delay to see I take of the jack from the sensor so what do you think the problem? Thank you.
Engine light came on for a small EVAP leak, it was fixed. Then it came back on for the same thing, the evap was fixed the dealer said my ECM level was low, they updated it, the light came back on same Evap diagnosis, I took it to a different VW dealer they said the same thing, low ECM level so they updated it and two days later today the light comes back on. So I’m just guessing the ECM itself is bad. So replacing it is where I’m Going with it
Perfect breakdown for the diagnosis. I have a question regarding electrical diagnosis. Took my Volvo to a few mechanics, all with another outcome. Draining of battery until about 10.33V even just quick stopping for gas, therefore always needing to boost. The computer showed up with pages of codes, though they are incorrect, as everything is properly functioning. Could it be the computer module that is malfunctioning with codes and battery drain, OR is the less than a year ago bought battery defective with a dead cell that causes these malfunctions? The dead cell could also explain why it does not drain to zero, rather 10.33V. My diagnosis has now fallen to this conclusion regarding my Volvo s80 2009. Thank you for any input or comment
Long shot but would anyone know if this would relate to a 2012 GMC Sierra I’ve changed the throttle body tps and the acceleration pedal and it was fine for a week and at random my gas pedal will quit responding and it will run super ruff you can pull over turn it off and turn it back on and run fine for a while then do it again
Wow thanks for the info. I have codes, for the throttle body, like 4 of em. Changed the entire throttle body, same codes, pro diagnosed it and the ECM is bad. Also when I get to say 30mph, reaches down to 20mph, it jerks slightly. The ABS and ESC light also is turned on with codes indicating multiple speed sensors, normally I’d think only one goes bad but multiple? Do you know if that could be a cause as well? I’m hoping the new ECM on the way fixes all that. (eBay $26, Sonata ’10) Thanks
My only question is can something possibly be wrong with my ECM if my vehicle cranks up but when I just turn the key to the start position and the dashboard turns on but I hear a few clicks at the same time which has me wondering what’s going on. Here’s a article of what I’m referring to: youtube.com/shorts/V29yr-Qgvpc?feature=share
My 2000 ram 1500 has all these symptoms. I fixed my iac motor and the scanner keeps throwing that code. This is auto zones obd scanner. It also read that my drive train ecm most likely needed to be replaced. I hope a new ecm computer fixes these problems. Can anyone give me their input on AutoZone’s new obd scanning tool for the store and its accuracy ?
Question pls. I have 2002 sentra 2.5 ser automatic with security system. My ecu is bad, so I need to replace It. How do u go about getting another one. U do see them on ebay but I’m not shure what numbers to look for. There are some number on the top and big K4 in the middle and other number at the bottom. Any help will be so helpful please
Diagnosing a bad PCM is not always that simple. Sometimes a defective module can mimic a bad PCM. You would think it’s a bad PCM when it’s not. I had a friend who accidentally put the battery backwards. After smoke settle it kept blowing a 200 Amp fusible link. Everywhere he took it to said it’s a bad PCM. He let me look at it. As an electronic engineer I know how circuits work. I pinpointed the problem to the factory audio amplifier. It had a shorted power diode. What that diode does is if you revered polarity it forward biases and overloads to self destruction shorting out the circuit making the fuse blow. I found one from a junk Television and replaced it. 😂
I have a 2008 Ford Explorer 4×4 wheel drive 161000 miles on it. Basically, rebuilt the whole engine. Having trouble with the engine light and it’s showing all 4 02 sensors bad I changed them all including the purge valve EGR valve air flow sensor I’m losing about a 100 miles a tank of gas. I rebuilt the whole engine all the Cam chains fresh tune up I did get a new ECM computer 2 years ago but that guy went out of business cause it was under warranty so now I gotta send it to some place to get rebuilt for 600 bucks. Other than losing fuel and the engine light staying on it, it runs and drives fine except for the gas.
Okay so I have a problem with my 2000 mustang GT, it won’t start it has fuel it has spark it has air and I’ve checked the grounds they’re fine, but my car still won’t start it will start on starting fluid but won’t keep running, starting to think it’s my ECM but I don’t know I took it out and looked at the motherboard it all looks fine no corrosion or anything could the ECM just gone bad?
2009 Kia Sorento, check engine light came on months prior to this: had occasional symptoms of possible clogged catalytic converter or even maybe fuel pump issues, drove it home one night, no new issues, next morning it crunk up but wouldn’t go in reverse and acceleration in drive was very minimal and no power. Drove about 4 miles and it cut off, popped hood and seen that the transmission fluid and blown back out the dipstick, added more fluid, cut it off and back on and it was as if nothing had happened at all. Drove about 2 miles to store, got gas, drove about 1/8 of a mile and there was a grinding sound if you will, car cut off and would not start back up (acted like it had a dead battery) I let it roll in neutral to my yard, where it remains. It wouldn’t crank back up then, 6/7 hours later I try to crank again and it would as long as I sit in the gas pedal. I check and confirm all fluids are good and leave it be for the night. Next morning it cranks up with no problem at all but now when I put it in gear it won’t move, revs up, but in no gear will it move… Any advice on what I have going on here?
My 99 Isuzu Rodeo 3.2L has been having several issues. 1. Hard shifting and it will not shift into overdrive. It actually seems to go back into 2nd when it should go into overdrive. I’m riding 2500-3000rpms going 50mph. It seems if I get up to 70mph and 3500rpms and hold it long enough something lets go finally and then rpms drop and the check transmission light starts flashing. 2. My Rodeo also has an issue with starting then immediately stalling. It used to be every other time I’d start it up. Now it’s nearly every time except on cold starts. But warm starts are ridiculous. Occasionally it’ll try to start without a single crank, but stalls. And then other times it cranks and cranks and cranks and still won’t start until I give it some gas. On these starts the idle is up and down and up and down til it settles between 500 and 1000rpms. On occasion it’ll stall out while idling but not driving. That’s even on cold starts. It just does whatever it feels like. There’s no vacuum leaks that I can find. There are no codes thrown for any of these issues. None. One person did have a scanner tool hooked up that showed a “pending” code for an O2 sensor failure. But now 3. My 4wheeldrive suddenly stopped working too. Doesn’t engage, the light doesn’t even come on when I hit the button. So do I have a damaged ECM or PCM? Is there a difference? I think my Rodeo’s brain is called a PCM. Any suggestions would be fantastic. I’m about to drive this off a cliff with no insurance. That’s how frustrated I’m getting.
2014 Ford Focus SE It all started with a barometric pressure sensor when I check the engine light, so just to be safe I changed all the ignition coils spark plugs MAF sensor and air filter to make sure it was getting proper air fuel ratio, turns out my 20 inch wheels must have damaged the PCM because Ford thought it would be a good idea to put the PCM so close to the wheel, PS putting 20s on my car wasn’t the greatest idea I know I know lol
Thank you! Should’ve watched THIS before putting it in the shop! My van was sitting in my yard waiting for my turn signal relay. Ran just fine before that. Replaced the relay went to start it…NOPE! Thought it was the fuel pump, just got off the phone with the mechanic and he said-“well, it’s NOT the fuel pump, sounds like it’s the ecu.” Dang it! When I tried using my OBD reader it malfunctioned, well….that explains it!
I’ve had a new starter and a new battery installed in my 2010 SS. It worked fine for a bit, but it started having a slow start again and putting it in limp mode constantly and giving me service stabilitrak. Any ideas? Chevy told me there’s so many different things going on with it but I believe it’s one solid issue and I am going to replace the ecm fuse. Clean my throttle body. If that doesn’t work I’m hoping it’s the spark plugs or something not too pricey. I bought a crankshaft position censor years ago and never never installed it because idk how to lol. Anyone think it could be that? Please give advice or opinions. Love my camaro just wanna get it back to its original state. Also when I bought the car someone had cut the catalytic convertor off with previous owner and put straight pipe on it and I’m missing an o2 censor. Let me know guys cheers
2001 Toyota Camry XLE 3.0l V6 I’ve been jump-starting my car a lot lately and this week I experienced new problems. The tach needle won’t rise to idle, the instrument cluster won’t light up, the transmission shifter stays locked in park, and the engine dies when I take the jumper cables off. I’ve replaced the alternator, and my 2-year-old battery has been a pos, so I’m replacing that too. You think its bad ECM, or lack of power??
Can somebody tell me what’s wrong with my Dodge ram 1500 SLT 2007 I put a brand new computer module in it and now it won’t say anything but when I put the old one back in it crank up but when I put the used one in everything comes on except it will not crank up it won’t say anything and somebody tell me what is wrong
So I have this Silverado that keeps burning the fuse that is for the ignition I took it to a shop to get checked out and they shop told me that it it’s possible it’s the starter and the fuse box but then I also got an opinion from another mechanic and he told me it’s possible that it could also be the ECM but I’m not sure who to believe if anybody could help by commenting that would be awesome 🙏🏽
Man I’ve got a 2000 Lexus LS400. Guy I bought it from said it might need a new ECM. It’s been throwing a bunch of codes. I just replaced the knock sensors and the knock sensor harness, VVT Solenoids, and I’m about to replace the connectors for those too. But the CEL comes on and it’s the same damn codes. Could be a bad capacitor on the ECM right?
My mustang GT 04 is running good and I keep getting codes po 316\\301 and I use my code reader and turn it off and my car is running good with no miss fire and after 20 or 30 miles it comes back on so I replaced every sensor in the car also the fuel pump and filter cam and crank the evap system new spark plugs and every thing I can think of or see and the car is running running much better lots power and shifts smooth but the engine light comes right back on so I will just take the bulb out of the check engine light socket
My truck would not start after it sat for 10 minutes when I turned the key the brake lights on cluster came on but nothing happened. The starter did not work nothing. I reset the ecm and then the truck started right up is my ecm bad? Its also throwing a code that my cat is bad but reset it and didn’t get a code until today a week later but I had to reset the ecm to get it started so no idea if it was the same code or another. The truck wouldn’t start until I reset the ecm. 1997 f150 4.6
2000 Toyota Camry, reverse works fine but drive 2 and L all just rev up and won’t budge. I don’t think the trans is bad as the fluid looks fine and the rpm’s adjust to being put in gear. Just gave out the other day after slipping 1st gear a lot. Damn gf not telling me the cars messed up. Lots of people on the Toyota forums fixed it with a new ecu, replaced the transmission for nothing.
hi i have a 2009 ford fiesta 1.6 tdci,i was driving it last week with no problems,then out of the blue a cog light came on which i have been told is the pcm light,the car died and wouldnt start for around 5 mins,eventually got it running and got it home,a friend plugged it in and a p0698 code came up,he said it was throttle pedal,so replaced that also put a new fuel filter after a day or 2 same thing happend,it wouldnt start so i put a forscan on it turned the pcm light off and it started,after 2 hours cut out again so i unplugged egr and it run fine for 2 days then the light came on again even with the egr unplugged,it has no problem starting but once that pcm light comes on the car will not start until i plug forscan into it and clear the p0698 code,is there anyone out there who can help it says sensor reference voltage c circuit low additional fault symptom circuit voltage below threshold……thanks in advance,jon,i have had all wiring checked and no faults,could this be ecu problem?
I have a 2007 chevy suburban .it started at sometimes and got worse, I would loose 1st and 4th gear. I replaced the shifting solenoids and checked the wiring in the transmission. And now it’s all the time I only have 2nd and 3rd. Chevy place wants me to by a new transmission. I also think I have fase code popping up. You think the transmission problem could be the tcm,or ecm ?