Troubleshooting another No Crank issue - LONG READ
Hey all,
I am attempting to troubleshoot another No Crank issue. After hours of research, I have found a ton of threads where people were experiencing the no crank issue, but no resolution. My hope here is to document my progress for anyone experiencing the same issue.
Initial Symptoms:
1. No crank with key. Car able to run and drive with remote start switch and key in igniton to the "On" Position. Remote start means using a momentary on switch to short pins 30 and 87 in starter relay socket.
2. No clicking or any other indications of start functionality when key moved to start position.
3. Fuel/Tach/Temp gauges work normally when key placed to “On” position. After start with remote switch, gauges stop working except speedo which functions normally.
4. No CEL, all other functions work, AC cold, driveability is what I would consider to be excellent.
Initial Troubleshooting:
1. Replaced clutch position switch (CPS), no change in behavior
2. Replaced ignition switch, no change in behavior
3. Replaced ECU, no change in behavior
4. There is 2.5VDC noted on starter relay pin 86. Voltage appears at key on and remains constant in all key positions, after key off voltage is gone after ~20 sec delay. Placing key to start has no effect on this pin voltage
5. Pin 85 starter relay to ground (G102) continuity good.
6. ECU pin 29 to starter relay pin 85 good, and not shorted to ground.
7. Code P0615 stored in DTC, MIL not requested.
8. Brand new battery
After instrument cluster (IDC) replacement. IDC replaced and calibrated via Techline Connect. *Note* You can’t update the mileage on a used cluster because Techline connect won’t allow it, it has to be a new IDC which is no longer available. Thanks GM…..
1. Change in behavior: Notable relay clicking when key placed to start seems to be ign relay.
2. Change in behavior: Dash activity consistent with what you would expect during a crank cycle (clock goes out, things happen)
3. Change in behavior: All instruments remain operational after remote (momentary on switch start)
4. No change in crank behavior, unable to crank with key and 2.5 VDC remains on the start signal wire to start relay.
Current Plan:
- Retest CPS and see if this changes anything.
- Look at PIDs to see if ECU is registering CPS function
- Disassemble fuse box and see if there are any anomalies
- Suggestions?
If you read all that, THANKS! Any ideas are greatly appreciated!
