Greetings, what'sup, hello. I'm Bee Jay from the C3 forum. But I have a friend name Gill. He has a friend and her name is Sandy. She has a C5 with electrical problems. Below is the letter Gill sent me. Any ideas?
Bee Jay


A lady (Sandy) here at Sunnyvale has a 1997 (first year) C5 Corvette bedeviled with electrical problems. Perhaps you could call on your profound knowledge and forum contacts to suggest a cause and solution. Here’s the list of things the car does:

1. ABS and Traction Control warning lights come on intermittently.
2. The radio sometimes shuts itself off when the ABS and Traction Control lights come on.
3. The gauges go to the red zone, then return to normal.
4. The security system resets itself, and locks or unlocks the doors while driving down the street.
5. Sometimes the radio won’t turn off, even with the ignition key removed.
6. Sometimes the radio turns itself on, and can’t be turned off (Sandy is getting pretty good at pulling the radio fuse).
7. When the ABS and Traction Control lights are on, the car subjectively feels like there is no power steering or power brakes.
8. When the ABS and Traction Control lights are on, the air conditioning doesn’t work.
9. Sometimes when the car is parked a while, it will start and immediately die. It will start after a 20 minute rest.
10. When the ABS and Traction Control lights come on, the digital display sometimes displays “80 mph limit” and the car won’t go over 80.
11. The above symptoms occur more frequently in wet weather than in dry weather.
12. The dealer replaced the PCM and BCM (Power Control Module and Body Control Module?) at great expense and the problems went away for a year.
13. Sandy read the PCM and/or BCM live under the battery tray – could water wash electrolyte leaking from the battery onto the PCM and BCM and affect them?

I’m guessing Sandy is not the only C5 owner to see these problems. Any suggestions beyond “replace PCM/BCM annually” would be appreciated. Is there a redesigned battery box with a drain?

Thanks!
-GILL

 

I'm just learning here but the best advice I've read on here is clean your grounds. Thanks Bill.

http://forums.corvetteforum.com/c5-t...tion-long.html

I got codes on my ABS. I cleaned my grounds and it went away. Soon after I got O2 sensor codes on both sides at the same time. I went back to my grounds, re-cleaned and made sure the pins were making good contact and it's been good since. Kind of surprising how a little thing a create such issues.

 

AND a weak battery will cause many weird issues.

 

Need some more information;

- Does "Sandy's" vette have the adjustable ride option ?

- Check the battery and PCM area for leaking battery, I recommend Optima Battery as they don't leak.

- Check the floor area in the passenger area for leaks ?

Need Codes ; here's how to get them.

The IPC display, the 20-character, vacuum florescent screen above the steering column that says "Corvette by Chevrolet" every time you turn on the key, is a powerful device. DIY Service Techs are going to be most interested in the IPC's ability to show diagnostic trouble codes (DTC) for all the modules that transmit them.
The "diagnostic display" mode is entered with the following procedure:
1. Turn on the ignition but don't start the engine.
2. Press the "reset" button to turn off any warning messages
3. Press and hold "options" and
4. While holding "options", press "fuel" four times within a 10-second period.
Inititially, the on-board diagnostics go into the "automatic" mode which shows each module's DTCs in a pre-set sequence:
• 10 PCM Powertrain Control Module page 6-357 - 6-361
• 28 TCS Traction Control system ABS on page 5-86
• ?? RTD Real Time damping page 3-136 (I do not have this option)
• 40 BCM Body Control Module page 8-405 UTD Page 8-727
• 60 IPC Instrument Panel Cluster page 8-508
• 80 radio page 8-213
• 99 HVAC Heater Vent-Air Conditioning page 1-118
• A0 LDCM Left Door Control module page 8-904 to 8-951
• A1 RDCM Right Door Control Module page 8-904 to 8-951
• AC SCM Seat Control module page 8-1064 -8-1082
• B0 RFA Remote Function Actuation page 8-676
For each module, all DTCs will be displayed. If none are present in a module, you will see "no more codes" on the ICP display.
There are two kinds of DTCs, "Current" and "History," designated with a letter suffix, "C" or "H". A current code indicates that the malfunction is present in the system whose module is displaying data. A history code indicates a problem existed in that module sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it is possible it's evidence of a previous problem, now solved, that was not removed by clearing codes. More likely is that a history code indicates an intermittent malfunction. "Intermittents" are the most challenging DTCs. An intermittent may have happened only once, may have happened more than once but is inconsistent in its appearance or may be happening on a regular basis but not at the time the IPC is displaying codes. History codes can also be caused by a current malfunction in a system that is not operating at the time DTCs are displayed. An example is the rear window defogger which doesn¹t operate until the BCM detects engine rpm. For history codes set by a system that does not operate with the key on and engine off, a special diagnostic tool called a "scan tester" is necessary to properly diagnose the malfunction.
Once the IPC has displayed all 11 modules, the system goes into the manual mode which allows selection of each module using combinations of DIC buttons. The manual mode can also be entered at any time during the automatic sequence by pressing any button except "E/M". Once the IPC displays "manual diagnostics," you may select a particular module by pressing the "options" button to go forward or the "trip" button to go back. Once a system is selected and a DTC is displayed, if more than one are present; press "gages" to move forward or "fuel" to go back.
To exit the diagnostic mode at any time, press "E/M". If you want to erase or "clear" codes, press "reset." Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory.

 

As already suggested, pulling codes is the first step. Based on the symptoms, it sounds like it may be a class 2 issue. Inspect the wiring in the left accordian tube. Start with post #610.....courtesy of Bill Curlee.

http://forums.corvetteforum.com/c5-t...n-long-31.html

 

You may want to investigate the grounds to make sure they are cleaned or replaced. There are 4 ground posts i believe that can freak out certain systems if they are fouled. Behind each headlight there is a post, under the battery and one more in the rear of the car-the exact spot escapes me. But often times people get short hex head self tappers and just attach the grounds to those since they are clean- and sink them.