I was waiting for a traffic light to change when my 2005 GMC Envoy XL (Denali) with a 5.3 engine just stalled and would not start for the next hour. After approximately 1-1/2 hours the engine started and I was able to make it home. The next day my son came over and we worked to find just what was the problem. Ok, my son did the work and I just watched.
We pulled the following P codes:
P0443 Evaporative emission (EVAP) purge control circuit
P0689 Computer control system ignition relay feedback circuit low voltage
P1682 Ignition 1 switch circuit 2
P2176 Minimum throttle position not learned
With these codes in hand it was off to the dealership. These are the instructions from the dealer as what to do:
1. Check for a blown ECM 1 fuse, if ok, it may have the high resistance at its connection of
the fuse. If fuse and resistance is ok, replace the ignition module. If this does not
clear the problem, (ignition module replaced).
2. Check Purge Valve replace if necessary. (Purge Valve replaced) If this does not
clear the problem,
3. Check and replace the PCM relay, (Relay replaced) If this does not clear the
problem,
4. Replace TBS (I replaced the entire TB because my TB was of an earlier type that used
rivets to hold the sensor on and was not available)
Nothing we have done to date has corrected the problem. The entire evaporative system has been inspected and no leak can be found. After each component was changed, a test drive was done using the same route, conditions and time and the engine fails exactly at the same place every time.
Although I am far from being a qualified mechanic, but being and engineer tells me a component is being adversely effected by the engine hear or heating up electrically.
Any help would be greatly appreciated.