GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hi there, I am cam. After clearing the codes, did the transmission react properly?
Strange, there must be another battery there somewhere as this is a 12V system. The code P064C is for a voltage issue on the glow plug controller or glow plug lines. Have you done any diagnostics there yet?
THats what concerns me. Its not a 24 volt system so this is VERY strange. I have schematics, but there are about 100 for this, so getting the system is vital. I will see if I can build a single document. I need to Vin to be sure.
Ok I am putting a document together.
Here you go.
It's worth a try, and they are common for failure. After that, it may take deeper diagnosis.
What color is the transmission fluid them?
Not all, lets look into the ignition switch still. Pop the tilt lever out and take the lower trim of the column off. With your multimeter set to DC volts, place the red lead on the red wire. With the switch turned on, test the other leads with the black wire. Record the reading and let me know what those are. Repeat the test on the red/white wire. Let me know the results.
Where does the position of the third battery connect to?
Quick test then, see if using a jumper cable to connect the positives works. If so then I would make it happen. Be sure all batteries are confirmed by load test as good and the charging system is up to the task.
What does the battery voltage read with the meter when this happens? I am wondering if we have an issue with the ground or even charging system dragging the voltage down with the PTO on.