2009 Aveo Is it the ECM?

Hi Folks,

So.. I'm hoping for suggestions as to where in the systems to look for the fault. Code U0001. No, there are no other codes,. I'm hoping a description of the "history" will help you who know these systems zero in on what I need to focus upon.

The car is not a beater, clean in and out. Roughly 150 k on it. Ran flawlessly.. until.. Last June, the car blew a heater hose at highway speed. Towed it home. I R&Red the head (shaved, new valve stem seals, gaskets, etc). Replaced water pump. Everything looked like new inside. Wouldn't start/run worth a dime. Over a period of weeks and months, different codes would come up, indicating different sensors were not functioning. Like a parade, one, then another, then another. I replaced both cam position sensors, crank position sensor, and coolant temp sensor. Last Fall it fired up nicely, and we drove it to family for Thanksgiving , 2 1/2 hour drive each way. No problems. After that, it then developed a "hard start", where it took a couple crank overs before the engine would fire. Then it was smooth as could be.

Not trusting it, we only drove it sporadically until Christmas, when we again headed to family. On the way, after an hour on the road, "check Engine" light comes on as we pass the Chevy dealership. We pull in. 5 hours later, they say the exhaust cam position sensor was faulty. They don't have the part. " Safe to drive home?" "Yes". Half way there, engine suddenly dies. Starts up. Smooth. Full power. 20 minutes later, as we are 2 miles from home, engine suddenly running rough. "Check Engine" light on. "Hold" light flashing. We barely get to the house. I run codes. The Exhaust cam position sensor (which dealer did not have in stock, so..) and U0001. I replace the Ex Cam Pos sensor. Won't start. Run codes. Only U0001.

I've looked at all the connections I can see. Everything is clean, no corrosion. With it's history of saying all those sensors were bad, one after another.. is it most likely the ECM itself is at fault? What are the odds each sensor was fine until.. with only minutes or more run time, a new/different sensor suddenly is bad?

With no other codes to give me direction as to what system is NOW unhappy, how do I narrow down the fault-finding. I'm not really handy with a meter, resistance checks, etc.

Any ideas where to look? What areas to focus on?

Thanks. My wife will be THRILLED to have this resolved.