Hey all, another C5 here that's been taken over by electrical gremlins. My 2001 Z06 had a suite of minor electrical problems when I purchased it last year, but some have grown since then. My current situation is that the car lights up with all traction control system warnings after driving for 5-10 minutes, followed by the reduced engine power warning another 5-10 minutes later.

Less recently this issue was even more pronounced. There was a point the dashboard would go crazy anytime I turned the car on (all warning lights on, secondary gauges all to 0 or max). In debugging that, I found a partially melted fuse, I believe this was #23 (BCM 2). I also noticed that I had left the battery terminals mildly loose after replacing it. The issues temporarily went away after cleaning the fuse and tightening the terminals. Since then I'd also fixed a malfunctioning front-right indicator light by cleaning the bulb contacts and repaired the ABS/EBCM module for a C1214 bad solder joint failure. I cleared all codes after fixing the ABS/EBCM and fortunately C1214 has been banished for good, but there's still plenty of new H codes to be pulled. The DTC list below was pulled directly after driving in the "current situation" described above.

Note that the car drives nicely. Besides the IPC issues, the only other symptom I've noticed is some unpredictability from the alarm; it occasionally goes off when it shouldn't. This has me thinking it's a communication issue, maybe caused by bad grounding as Bill talks about in the sticky:
https://www.corvetteforum.com/forums...tion-long.html
However, I'm having trouble seeing images and navigating through that thread. So I was wondering if anyone has opinions or even a more specific diagnosis based on the codes shown, before I go searching for chassis grounds.

DTCs:
PCM
P0650 H C, MIL control circuit
P1626 H, theft deterrent system fuel enable circuit
TCS
U1301 H, class 2 circuit shorted to battery
C1224 H, RR wheel speed sensor input signal is 0
C1228 H, RR excessive wheels speed variation
C1235 H, RR wheel speed circuit open or shorted
BCM
U1255 H, generic loss communications
U1096 H, loss of communications with IPC
U1016 H, loss of communications with PCM
SDM
U1301 H, class 2 circuit shorted to battery
IPC
U1255 H, serial data line malfunction
U1016 H, loss of communications with PCM
U1064 H, loss of communications with BCM
U1040 H, loss of communications with TCS
U1176 H, loss of communications with RFA
U1088 H, loss of communications with SDM
RADIO
NO COMM (replaced with aftermarket)
HVAC
U1064 H, loss of communications with BCM
U1096 H, loss of communications with IPC
U1160 H, loss of communications with LDCM
U1255 H, serial data line malfunction
LDCM
U1064 H, loss of communications with BCM
RDCM
NO CODES
RFA
U1255 H, serial data line malfunction
U1064 H, loss of communications with BCM

 

Were the codes cleared and all of these showed up after that one drive? If not, I would clear all the codes and monitor after each drive to see which code or codes pops up. You're in one of those can't see the forest thru the trees kinda code count.

 

The only DTC that’s sticks out is the U1301 which is the SDM (Airbag Module) data line is shorted to battery…not knowing how much electrical experience you have is remove the SDM fuse 16 in the IP Fuseblock and see if your issue comes back…I would delete all those history DTC’s if you can…airbag will be disabled so don’t get yourself into an accident.

 

Yup, unfortunately these codes are all new after clearing then going for a drive It seems unusual then to have such an array of history codes, but maybe indicative of an intermittent issue, or something that only goes current while driving?

Worth a try, I'll pull that fuse 16 tonight and see how that code changes.

 

If you have and know how to use a DVOM check the voltage on Pin 2 on the DLC when those issues pop up…you can use pins 4 or 5 for your DVOM ground…if there are no communication issues on this wire which all the modules communicate on you will see maybe .2 to .4 volts which fluctuate with key on or engine running….is pin 2 is shorted to voltage you will see system voltage…with a lab scope you will see a digital 0-7 volt square wave if there are no issues.