Symptoms of a Bad or Failing Engine Control Module (ECM)

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The engine control module (ECM), also commonly referred to as the engine control unit (ECU) or powertrain control module (PCM), is one of the most important components found on virtually all modern vehicles. It essentially functions as the main computer for many of the vehicle’s engine performance and drivability functions. The ECM takes the information from the engine's various sensors and uses that information to calculate and tune engine spark and fuel for maximum power and efficiency.

The ECM plays a crucial role in newer vehicles, where many of the essential functions of the car are controlled by the ECM. When the ECM has any issues, it can cause all sorts of problems with the vehicle, and in some cases even render it undrivable. A bad or failing ECM may produce any of the following 5 symptoms to alert the driver of a potential problem.

1. Check Engine Light Turns On

An illuminated Check Engine Light is one possible symptom of a problem with the ECM. The Check Engine Light usually illuminates when the computer detects a problem with any of its sensors or circuits. There are cases, however, where the ECM illuminates a Check Engine Light mistakenly, or when there is no issue present. Have a mechanic scan the computer for trouble codes to diagnose whether the issue is with the ECM, or elsewhere on the vehicle.

2. Engine Stalling or Misfiring

Erratic engine behavior may also indicate a bad or failing ECM. A faulty computer may cause the vehicle to intermittently stall or misfire. The symptoms might come and go and not appear to have any sort of pattern to their frequency or severity.

2. Engine Performance Issues

Engine performance issues are another symptom of a possible problem with the ECM. If the ECM has any issues, it may throw off the timing and fuel settings of the engine, which can negatively affect performance. A faulty ECM may cause the vehicle to experience a reduction in fuel efficiency, power, acceleration.

4. Car Not Starting

A bad ECM may lead to a vehicle that won’t or is difficult to start. If the ECM fails completely, it will leave the vehicle without engine management control, and will not start or run as a result. The engine may still crank, but it will not be able to start without the vital inputs from the computer. Car-starting problems are not exclusively caused by the ECM, so it's best to get a complete diagnosis by a professional technician to accurately determine the cause.

5. Poor Fuel Economy

Bad fuel economy may occur from a failing ECM. A faulty ECM disallows your engine from knowing how much fuel to burn in the combustion process. Typically, the vehicle consumes more fuel than it should in this situation. You’ll end up paying more for gas than you would with a functioning ECM.

The ECM plays a vital role in engine performance. Any issues with it can cause major problems with the overall functionality of the car. As the computer systems found on modern vehicles are quite sophisticated and complicated, they can also be difficult to diagnose. For this reason, if you suspect that your vehicle’s ECM is having an issue, have the vehicle inspected by a professional technician to determine if your car will need an ECM replacement.


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Rigoberto

9 years of experience
706 reviews
Rigoberto
9 years of experience
Chevrolet Equinox - Brake Pads Replacement (Rear) - Niles, Illinois
Rigo was great! He got there early, finished the job early, left everything clean. He changed my rear pads and rotors. The original quoted time was 90 minutes, he was done in about 60. He knows what he is doing and I am recommending him to all my friends and coworkers.
Mercedes-Benz C250 - Brake Pads Replacement (Front, Rear) - Chicago, Illinois
Rigo is a maverick hands down. Don’t take your car for work elsewhere. Especially great at Mercedes—this guy knows his profession! I will be using him for everything related to my car going forward.

Arturo

25 years of experience
35 reviews
Arturo
25 years of experience
Kia Forte - Brake Pads Replacement (Front) - San Diego, California
ARTURO is great! very professional , fast, replaced my front brake pads and oil an filter change. everything now works and works well. Brakes have much improved stopping power and engine is smooth and quiet.Arturo is also kind and thoughtful. "Your mechanic" is very fortunate to have Arturo Lopez represent your company. I enthusiastically recommend him and "Your mechanic> as a fine operation Best regards to the Team Peter Marto
Nissan Maxima - Brake Pads Replacement (Front, Rear) - San Diego, California
Arturo was prompt and completed my brake repair, including new rotors in a very efficient manner. I am very pleased with the quality of the work and the parts and will definitely look to have him service our other car in the near future.

Scott

32 years of experience
345 reviews
Scott
32 years of experience
Lexus IS250 - Brake Pads Replacement (Rear) - Denver, Colorado
Always on time, speedy, professional, and pleasant to interact with. The work is always consistent and we'll done. I can't reccomend Scott highly enough!

Michael

10 years of experience
15 reviews
Michael
10 years of experience
Nissan Sentra - Brake Pads Replacement (Front) - Conyers, Georgia
He was promptly on time and got the job done efficiently in a timely manner. I really appreciate the rapid respone on getting the job done! I would most definitely use this service again.

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