Here are the four most common symptoms of a bad ECM computer: There are many reasons your Check Engine light can turn on. There are a few things that can tip you off that there’s a problem. Once again, you’ll need to take your car to a mechanic to be sure. If you’ve replaced these parts and your car won’t start, your ECM is the most likely cause.
Of course, there are other reasons a car may not start, including a bad starter or a blown alternator.
These range from emissions problems to faulty O2 sensors to problems with the ECM. What are the symptoms of a bad ECM computer?