Yes is is highly unlikely that 3 shops would not get any error codes if they existed.
The check engine light is supposed to light up when the PCM sees a sensor out of a predefined range.
It is possible that the light has an intermittent short, causing it to illuminate.
I would check the wiring from light to the PCM, there may be a wire that is pinched or lost some insulation, causing a short to ground.
I would certainly not trash the car, if it is running OK, this may be a simple fix.
Generally when a PCM is bad, the car will not run or run very bad, and the PCM does and internal check evertime the ignition is turned on.
Sunday, October 18th, 2009 AT 8:56 AM