Top 8 Symptoms and Causes of a Bad PCM

What is Powertrain Control Module?
The PCM is known as the brain of the vehicle. The PCM is also known as the engine control module (ECM). It is a self-propelled control system installed in your car.
The main function of the PCM is to collect data from different parts and sensors of your vehicle engine. After collecting the data, it uses data to produce the desired power and efficiency of the vehicle by controlling the engine’s spark and fuel.

Symptoms of a bad PCM
The probability of permanent failure of your car’s powertrain control module is very low in the latest vehicle models, but it may fail with time. As the powertrain control module goes bad, it generates one of the below-given symptoms:

1) Check Engine Light
The check engine light is one of the major symptoms of a bad PCM or ECM. However, this light may illuminate due to many other problems in your car. For example, issues with wiring, MAP sensor, IAT sensor, or engine overheating may also trigger check engine light.

2) Reduced Engine Performance
The bad performance of your car’s engine can be the reason for a bad powertrain control module. As the powertrain control module goes bad, it doesn’t properly control the fuel and the spark timing. When the fuel and spark timing disturb, this results in poor performance of the engine.

3) Issue in Shifting Gears
A problem in gear shifting is also one of the common symptoms of PCM failure. The PCM controls the functions of the transmission system and the engine of your car. Thus, the issues with the powertrain will indirectly be the issues with your car’s powertrain control module.

4) Issues in Starting
It is the job of the powertrain control module to ensure that every component it controls is working properly. Timings of the ignition are one of these tasks. When the timing is off, the spark plug doesn’t ignite the air-fuel mixture.

5) Misfires
If your car often backfires or misfires, then it needs a proper check-up by a professional. In the service centers, the professional will find the trouble codes and will let you know the exact issue with your car.

6) Failed Emission Test
A healthy powertrain control module ensures the minimum emission of exhaust gases and improves engine performance. However, when the PCM goes bad, it doesn’t control the emission efficiently and increases the emission rate.

7) Poor Fuel Economy
A reduction in fuel economy is often a sign of a bad PCM. When the powertrain control module goes bad, your car couldn’t be able to detect exactly how much fuel it has to burn in the combustion procedure.

8) Code Errors related to PCM
The bad PCM related trouble code is a most common symptom. A trouble code is created in your car’s computer whenever a car faces an issue. Use a proper OBD2 scanner to read the code. If the code is related to the PCM, then you are lucky that you detected the proper issue at once.

Causes of a bad PCM
1) Engine overheating problems
2) Manufacturing Issues
3) Electrical Issues
4) Physical Damage
5) Faulty sensors

--- Time Stamp --
00:00 - Introduction
00:37 - Powertrain Control Module Function
01:17 - Symptoms of Bad PCM
05:16 - Causes of Bad PCM

Disclaimer:
This video is just for educational purposes only. We are not in the auto repair business nor publish automotive service manuals. This video is not reviewed or authorized by any vehicle manufacturer. This video is intended only as general guidance. Every system is slightly different, so refer to the owner’s manual of your vehicle for any specific information about your model. Remember that only proper service and repair procedures will ensure your car's safe and reliable operation.

Copyright Disclaimer:
Copyright Disclaimer under section 107 of the Copyright Act 1976, allowance is made for “fair use” for purposes such as criticism, comment, news reporting, teaching, scholarship, education, and research. Fair use is a use permitted by copyright statute that might otherwise be infringing. Non-profit, educational, or personal use tips the balance in favor of fair use.

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[twinscrew.]

I have replaced coolant sensor 3 times and wiring is perfect and truck stalls then starts and runs rich and check engine light is on with no codes any idea's

[pecanstamped]

Hmm, my heat went out and mechanic can't figure it out. Truck stalled once but has been fine since.

[AJDBroski]

I had a '05 VW Jetta, it stalled while i was driving on the street. Code P2177 popped up, so i changed fuel pump, MAF sensor, clean fuel injectors and replaced spark plugs. My last resort was the PCM was bad, but wasnt sure because the part was $600. But hearing the beginning of the video you said it also plays a part in the AC (which also was another problem). I changed the AC compressor, AC relay, ac radiator fan, vacuumed and charged it. So do you think it was the PCM the whole time?

[wajihwakim]

great info thank you, i have vw mk5 R32 having this P0351 code its intermittent misfire with rough idle, changed new coil original vw and all spark plugs changed and connectors. i can see a strong spark out of the coil for cylinder 1. how likely this issue is caused by a faulty ECU and if its the ecu would the coil still fire normally and constantly maybe signal sent wrong from ecu? the only code coming is P0351 would appreciate your feedback

[WarofWolvess]

I’ve got a 99’ Ford mustang Gt. I’ve replaced fuel pump. Fuel filter. Injectors. Alternator. Fuses. Still will not start. Cranks and tries to start but it can’t. Fuel pump is working too. Says no communication to the pcm. I’ve done everything else. Will buying and installing a pcm make it run?

[kevinhollingsworth]

I have a chrysler 300 2006 check engine light came on transmission started acking funny not charging gears getting code p0700 and p0748 got a transmission out of 2006 dogde charger put it in this transmission giving code p7048 and p0700 anyone kno what is problem

[xxaquzzxx-]

Hey I think this is wrong with my 2013 dodge dart, it starts fine. But when I am randomly going down the road it starts jerking back and forth. I noticed I get bad fuel economy as well. I have a code reader and it’s says pcm/ecu is not registering data correctly. I am positive this is it. Thanks

[Gmackk]

I’ve got an 06 Chrysler 300c. It’s the hemi. Getting code p0300. Wouldn’t idle when I first got it just kept stalling. It’s got no cats on it. I changed the spark plugs and coil packs an it started up an ran fine! I got cats for it an I was only able to get passenger side cat on. Gonna have to have a shop do the driver side but now the p0300 code is back and the car will idle but when u put it in gear it stalls out. Didn’t have this issue until I put passenger cat on? Need some suggestions! Gonna change out the fuel injectors next but what would be your advice?

[amandapegg]

I have taken my Kia Rio to 4 different shops and they can’t figure out what is wrong. It turns and acts like it’ll start, but won’t. I have changed the gas tank, spark plugs, new battery, camshaft, and crankshaft. The last mechanic said it has to be the ecm but wasn’t sure. He said he didn’t have the time to go to junk yard and the other 3 shops told me to just buy another car. I can’t cause I ended up hurting my back and doctor won’t release me to work so I can’t get another car being a single mom. Any ideas? The problem before this was when I put gas into car would die and take several times to start. Also was running code p0343, p0650, p0016, p0172, & p0456. I fixed all but the p0172, p0456 & p0650. After clearing the codes I only get p0650. I thought about replacing ECU then if that didn’t help change the canister purge valve.

[fredlafleur]

I need help please anyone ever got this symthoms start the vehicle let it run in about 15 20 minutes just randomly dies and try start back it would crank just like when u have a faulty fuel pump but i put new fuel pump, coolants temperature sensor, fuel rail sensor, oxygen sensors but what make me think it the pcm i unplugged airflow sensor car did not turned off after the car die i have to wait for atleast 15 minute for it to start back

[..........]

I have a c0298
P1120
Wire was damaged and replaced. I erased codes works fine. I turn off vehicle and the codes will appear again.. I erased codes again. Works perfectly. Turn off and back on again and codes reaper

[charlieallisoni]

Where is the pcm located in a 2012 ford F150

[joegamer]

My 2008 mazda mx5 blows 15A engine fuse when i turn on the ignition switch and scanner says error code u0100 that is for lost communication with pcm and don't know if its a pcm problem cause sometimes the car was running fine then the performance drops and have to rev up but at around 4k rpms the car just dies randomly and the fuse keeps blowing and nobody wants to work on so i'm here 😢

[panchoflores]

My 05 tundra has like 4 faults some say 02 sensors replaced but still comes back after 20 mnt drive one of them says module. Can it be comp.?

[jasonb]

Got an 05 duramax that's been acting like it has a short and finally pulled a p0601 code