Engine Mechanical problem
2004 GMC Envoy 6 cyl Two Wheel Drive Automatic 58000 miles
My " check engine soon" and " reduced engine power" lights come on. When this happens it feels as if the vehicle goes dead; however, it doesn't but I find myself having to coast into the closest parking lot to avoid being hit. Each time it's done this I have taken it to 2 different autozones for them to check it out. Both times the hand held system comes up with this P1680 reading. When they look the code up it tells them ECM failure. The part even refurbished runs $460 with a core charge. I'm trying to decide on if I should go with these 2 readings or actually take it to a dealership and have them put the vehicle on an actual diagnostic machine. A co-worker told me it also could be the fan motor harness. Any suggestions?
You should take this vehicle to the dealer. Autozone is not a place to take your vehicle to be fixed or diagnosed. People at autozone sell parts they dont fix vehicles. Dont put an ecm in this vehicle without proper diag.P1680 is an accelerator pedal position code. Here is a bulletin that might help. Service Engine Soon Light On, P1680 (Reprogram or Replace PCM)
Models: 2004 Buick Rainier
2004 Chevrolet Trailblazer
2004 GMC Envoy
2004 Oldsmobile Bravada
with 4.2L Engine (VIN S - RPO LL8) Some customers may comment on the Service Engine Soon Light coming on. Upon investigation, the technician may find a P1680 diagnostic trouble code.
Check the resistance of the accelerator pedal position sensors using the procedure in the appropriate Service Information for DTC P1680.
If the resistance of the accelerator pedal position sensor is within the specifications shown in the Service Information and the vehicle was built prior to the following VIN breakpoints, then reprogram the PCM with the latest calibration.
If the resistance of the accelerator pedal position sensor is within the specifications shown in the Service Information and the vehicle was built after the following VIN breakpoints, then replace the PCM. If the resistance of the accelerator pedal position sensor is outside the specifications shown in the Service Information, then continue with the diagnostics for DTC P1680. VIN Breakpoints
" Vehicles built at Oklahoma City Assembly Plant - 46192755
" Vehicles built at Moraine Assembly Plant - 42315833 post back with what you find. My advise take it to a professional.