Problem

[maa171]

I bought a Chevy cobalt 2L 2008 3 months ago it has a clean title 53,000 miles well maintained by one owner an elderly couple.

The car was running perfectly but one day when I was driving the car began shaking and the locks would lock and unlock very quickly by themselves and then the car slowed down a lot and the speedometer stopped working; it remains at the bottom even if the car is moving.


The check engine light is on and the dash says power steering, and is no longer giving me information about the car such as tire pressure.



I took it to my personal mechanic and he took it out for a test drive and said that the transmission isn’t shifting, he checked the power steering (its electric) and everything looks good on it. He told me he had a car that’s done this before and updating the computer fixed and that I need to go to a chevy dealership to do it.



So I took it to them asked for them to update the ECM, they did it and it didn’t fix the problem I asked for a diagnosis of the vehicle and they said it has multiple problems being:


-No communication with trans control module or with power steering module, has multiple body control codes U101, U102, U1101
So basically the computer isn’t communicating with the other parts of the car; because the diagnostic was so unclear they didn’t even charge me for it; they said they would have to work on the vehicle by the hour unplugging various modules and it would cost $100 an hour. I figure before I fall into this money trap I should ask the internet at large if they know what’s wrong or a possible solution.


It’s just mind boggling why such a new car with so little mileage would have such a severe problem.


Thanks in advanced and sorry for the long post

[tomj76]

Sorry you didn't get a reply.

I know it's been a long time, but I'll add my two cents for anyone who sees your question.

First, a wide spread failure like yours normally comes from a single cause. Unfortunately you'll need to check the basics, for example the battery voltage at a couple of critical points, and as stated a minimum system.

I'd start by checking battery voltage at the ECM. If that's low, then I'd check it again while disconnecting each module until it is restored. Once the battery voltage is OK, I'd run the car with just the ECM connected to see if the engine runs OK. Then I'd reconnect one thing at a time, for example add the transmission module, see if it runs/drives OK. Then add the power steering and repeat. Add each module and retest until you find one that brings the system down.