The One

Driving along normally at 45 (semi-bumpy road).
Suddenly the dash lights up - (Active Handling, Security, etc.).
The DIC starts flashing Service Vehicle Soon, Service Tire Monitring System, Reduced Engine Power, etc. The car never actually went into Reduced Engine Power mode, but the DIC kept flashing it.

Then, for about 30 seconds, the gauges flat-lined. Everything went to 0 including the fuel gauge, volts - everything. Then they came back up. The whole time the car ran fine - no hiccups, spurts, stalls - nothing abnormal.

Pulled over and cleared codes. Everything except PCM P1626 cleared. That code instantly came back after clearing it. Got the car home and pulled all codes. Pretty much all of them were set. The notable ones were that P1626 PCM and an A1 RDCM NO COMM (right door control module.) The right side window/door locks are now dead.

What the hell happened?

The only thing done to the car recently (3-4 weeks ago) was the addition of an Optima Red Top to replace the stock battery which was going bad. A few weeks prior to that I had a shift light put in and wired to the harness under the dash (not over to the passenger side like many people do.)

Any help is appreciated before I trek to the dealer to put that GMPP extended warranty to work!


[Modified by The One, 9:25 PM 6/23/2004]

jays98

just happened to me, was the a/c on? if so check the passenger side floor to see if it is wet near the computer, if so your a/c drain is clogged, pull the hose off from under the hood in the center of the firewall and poke a coat hanger or something of the sort in there to unlclog the drain

The One

Thought of that myself. Everything's dry in the passenger footwell.

CAPN17

You may have a bad ground connection that the bumpy road really kicked out of contact, it sure sounds like an interruction of electric flow.

LittleBoyBlu99

Keep us posted

yellowvette837

I had this happen about a year ago. (on the way to the dealer to fix another problem)
They never figured it out, but it also has never happened again

ToplessTexan

Sounds like a momentary voltage dip to me. This happened to me exactly once (when I was running late for a date of all things.) Gets your attention doesn't it? I later cleaned and tightened up the battery terminals which *seemed* a little loose though that might just have been wishful thinking on my part.

The One

I'm leaning toward that explanation as well. Car's in the shop today, so hopefully it can be diagnosed quickly. I'll keep you guys posted.

Hiteck

I recently got all of these on my DIC too. I pulled the entire interior out of the car to install insulation. While I was doing this, in the drivers side rear storage compartment (coupe), there is a module (don't know proper name for it) with two connections into it. When I disconnected it and pulled it out of the car, I cranked it up to pull forward into the garage. The dash went haywire just like you explained. Said everything you said, plus inoperable shocks, reduce speed to 80mph, and a few others. Scared me stiff. So later I hooked it back up and cranked up the car, no problem. If you have F45, maybe the wiring to this may be loose?

wrustywrench

my shift lite is wires under the dash,, not in pass side,, no problems here so far......sounds like a bad connection,,,I get a code for my right door every now and then,,,,,still works fine

0vetteshop

The C5 is unique in that all 10 modules communicate over a serial data line.For some reason,when the door control module loses power or ground indicated by "NO COMM" on the DIC,it causes havoc with the other modules.
The harness to the door controls routes through the rubber acordian grommett located at the front door jam.If you pop the grommett out,you can pull out 2 connectors out of the door jam,one blue and one black.If you disconnect the black connector,you will see that the female connector pins have spread causing poor contact on the orange wire (power) or the ground wire (black).You can insert a pick into the back side of the connector terminals to close up the gap in the terminal creating proper contact with the male end connector.
This is a common issue that is caused by stress on the harness from opening and closing the doors over time.Actually,you can recreate the condition by simply operating the windows while swinging the door open and closed at the same time
Good luck

The One

Knew you'd have some good info for me C-5 TECH.
Thanks a million.

I did just pick up the car and that is one of the things the shop (not a dealer) did. They basically went through all the ground points on the car to make sure they were all clean and tight. Got the car home just fine - no codes or issues whatsoever. I got on it - just a little , to make sure though.

Thanks you all for the feedback.

Dirty Howie

Wow!!!.......you really seem to know your stuff!!!!

Any chance you could look at my post about Pinging/Predetonation in this forum??

Thanks.