Skip the auto shop - Our mechanics make house calls

Q: Engine Computer Issues (spark plugs & coils were changed 5 months ago as well).

asked by on

About 6 months ago my eml/service & brake lights came on. The car started running rough & wouldn't go over 50mph. I had car towed to mechanic. After much investigation, the mechanic said the engine computer would need replaced. He didnt do this without much investigating. He is the local mechanic who does all imported cars in my city. He gets very high remarks from customers. He purchased a new computer from the BMW dealer. He did the programming and installed the unit. I got the car back and all was good. Last week, out of nowhere, when I started the car, the eml/service lights came on. The car was running rough again. This time the lights didn't always come on at startup. When not on, the car would run perfect. Car is back to mechanic. The codes he is getting are saying the eng. computer is a problem. He is still investigating because he doesn't understand how this happened. I am very confused too. Any ideas on what could be happening and what we should do? Help?

My car has 80000 miles.
My car has an automatic transmission.

A: Do you have ANY aftermarket electrical equi...

Do you have ANY aftermarket electrical equipment in the car? Such components can impact the function of the PCM. Also, check the alternator output and stability. If the power supply to the PCM is not within specification, that could damage or alter normal function of the PCM. Check for defective, inadequate, or missing ground wires and terminals as well.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: check engine light on 2002 325i bmw

Hi there: Anytime an error is detected it stores a trouble code in the ECU which illuminates the check engine light on your BMW. In order to determine what's causing issues, or causing the check engine light to illuminate, you'll...

Q: Speedometer and gas gauge not working

This may be related to a short or a faulty instrument cluster voltage regulator. The instrument voltage regulator regulates the voltage supplied to the various gauges in your vehicle’s dash. When this is not working properly, this may cause the...

Q: The engine cranks and sputters out, the car has to be jump-started

Hello. Most of the time this is caused by a battery. The battery may be shorting internally and intermittently. It needs to be load tested to know for sure. If it is definitely fine, then the issue may be in...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.