New Clutch Replacement + REP Mode (Reduced Engine Power)
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New Clutch Replacement + REP Mode (Reduced Engine Power)
Just had a clutch replaced in my '02 C5 Z06, and after the tech attempted to start the car, it started producing REP messages.
I had the car towed home, and I started investigating the problem. Upon start-up, it throws P0102HC & C1278H codes. The P0102HC had always been their prior (heads/cam setup), and never caused REP issues before though. I think the C1278H might be a by-product of the PCM going into REP mode.
To describe the problem, sometimes when it fires up, it immediately goes into REP mode/throws codes. Other times, it will start without throwing issue, until I pop the RPM's above ~1500 and it REP's. I also noticed if I slowly bring the RPM's up, it will allow me past 1500, but if I bring them up quickly, REP is triggered.
After a few start up attempts, I started to get a few low oil-level warnings. Dipstick says full, so I checked the oil-level sensor wiring. It was among the wires routed passed the starter/headers, which had been melted in a few spots, prior to the clutch replacement. Yesterday, I cleaned up the bundle of wires, and re-shrink wrapped them, making sure nothing is touching or potentially shorting anywhere. Still got random low oil warnings. I then read the low-oil sensor works like a switch, and is normally open. When the oil level is within range, the switch closes. To test this, I stuck a wire in the oil-level sensor plug, and shorted the two prongs. No more oil-level complaints, but still have the REP issues. Did the oil-level sensor go bad when the wires were melted/shorted?
Anyway, moving along, I went through all the grounds, and made sure they're secure/tight. Didn't find anything loose. I shook and wiggled all the wiring harnesses hoping to isolate the problem, but nothing changed. Disconnected the throttle body to make sure the connectors were clean, and all looked good. I then checked the ABS/wheel sensor connectors, and they all looked good, however I don't know of anyway to actually test them with a meter, etc. Checked all the coil plugs/wires, and they're all good. I have a FAST 90 intake (w/ LS2 TB), so I don't have that black bracket where a lot of people experience wire chaffing next to rear engine/firewall. Hell, I even swapped the 02 sensors (LGM headers) incase they were accidentally installed backwards, but still REP's either way. I took off battery cables, looked for corrosion (none found), and used Battery Tender over night to ensure its good. Battery is fully charged, and appears fine.
I'm so tired after troubleshooting this for two full days now, I know I'm probably forgetting to mention other diagnosis steps I've taken. Long story short here, I'm concerned when the tech re-installed my headers, he wasn't aware of the (prior) chaffed wiring by starter/headers, and they may have been touching when the key was turned on, thus potentially shorting out components such as PCM/ECU, TB, APP, etc.
Has anyone ever heard of, or actually encountered, a damaged component due to something shorting around the G106 ground location? I know Bill Curlee is the man when it comes to electrical issues on these cars, and I've tried to research most of his suggestions before posting on here. Anyone who has any experience or suggestions with this, it would be GREATLY appreciated!
Thanks,
-Kris
I had the car towed home, and I started investigating the problem. Upon start-up, it throws P0102HC & C1278H codes. The P0102HC had always been their prior (heads/cam setup), and never caused REP issues before though. I think the C1278H might be a by-product of the PCM going into REP mode.
To describe the problem, sometimes when it fires up, it immediately goes into REP mode/throws codes. Other times, it will start without throwing issue, until I pop the RPM's above ~1500 and it REP's. I also noticed if I slowly bring the RPM's up, it will allow me past 1500, but if I bring them up quickly, REP is triggered.
After a few start up attempts, I started to get a few low oil-level warnings. Dipstick says full, so I checked the oil-level sensor wiring. It was among the wires routed passed the starter/headers, which had been melted in a few spots, prior to the clutch replacement. Yesterday, I cleaned up the bundle of wires, and re-shrink wrapped them, making sure nothing is touching or potentially shorting anywhere. Still got random low oil warnings. I then read the low-oil sensor works like a switch, and is normally open. When the oil level is within range, the switch closes. To test this, I stuck a wire in the oil-level sensor plug, and shorted the two prongs. No more oil-level complaints, but still have the REP issues. Did the oil-level sensor go bad when the wires were melted/shorted?
Anyway, moving along, I went through all the grounds, and made sure they're secure/tight. Didn't find anything loose. I shook and wiggled all the wiring harnesses hoping to isolate the problem, but nothing changed. Disconnected the throttle body to make sure the connectors were clean, and all looked good. I then checked the ABS/wheel sensor connectors, and they all looked good, however I don't know of anyway to actually test them with a meter, etc. Checked all the coil plugs/wires, and they're all good. I have a FAST 90 intake (w/ LS2 TB), so I don't have that black bracket where a lot of people experience wire chaffing next to rear engine/firewall. Hell, I even swapped the 02 sensors (LGM headers) incase they were accidentally installed backwards, but still REP's either way. I took off battery cables, looked for corrosion (none found), and used Battery Tender over night to ensure its good. Battery is fully charged, and appears fine.
I'm so tired after troubleshooting this for two full days now, I know I'm probably forgetting to mention other diagnosis steps I've taken. Long story short here, I'm concerned when the tech re-installed my headers, he wasn't aware of the (prior) chaffed wiring by starter/headers, and they may have been touching when the key was turned on, thus potentially shorting out components such as PCM/ECU, TB, APP, etc.
Has anyone ever heard of, or actually encountered, a damaged component due to something shorting around the G106 ground location? I know Bill Curlee is the man when it comes to electrical issues on these cars, and I've tried to research most of his suggestions before posting on here. Anyone who has any experience or suggestions with this, it would be GREATLY appreciated!
Thanks,
-Kris
