dtc error "no comm"

[tripleblackc5]

Yesterday my car turned into Christine.
All normal driving down the road and alarms start going off, abs traction control, fuel gage goes to zero, then back again....then the radio goes off, and then a little later back on and off again. Then I hear the doors unlock and then relock again, then reduce power warning comes on.

I finished my drive to the dentist for some more pain, came out and the car would not start. Popped the hood....like I could do something, got back in the car ...it started so I was able to get home. After that ..no more starting. Checked all fused battery voltage and connections ok.

Check the dtc for alarms, error message said no comm across the board.

Christine did a little more magic overnite, locked the doors on me....of course it my pushbutton key device doesn't work so i had to manually unlock it...and the horn goes off. ...will the key stop the horn...yes, and now it will also start it....till I drive it some where i guess.

Any way , I thought people would enjoy the true story.

So my basic problem is no comm

Help

tripleblackc5

[leadfoot]

I have had the same thing happen x2. Once it was a dying battery and the second time it was a corroded ground made worse by wet weather. HAs it been wet where you drive? What is the condition of the battery? Best of Luck

[Cobra4B]

Have the battery load tested and start checking the grounds for corrosion etc.

I had my actual gauge cluster go bad in my old Z06... was driving and all gauges went to zero other than fuel and the DIC wouldn't show anything. Turns out the main board went bad and had to send it off to be repaird to a CF member.

However, since your door locks and everything else are involved I doubt it's anything like that.

[1999 White C5 Coupe]

Originally Posted by tripleblackc5

Yesterday my car turned into Christine.
All normal driving down the road and alarms start going off, abs traction control, fuel gage goes to zero, then back again....then the radio goes off, and then a little later back on and off again. Then I hear the doors unlock and then relock again, then reduce power warning comes on.

I finished my drive to the dentist for some more pain, came out and the car would not start. Popped the hood....like I could do something, got back in the car ...it started so I was able to get home. After that ..no more starting. Checked all fused battery voltage and connections ok.

Check the dtc for alarms, error message said no comm across the board.

Christine did a little more magic overnite, locked the doors on me....of course it my pushbutton key device doesn't work so i had to manually unlock it...and the horn goes off. ...will the key stop the horn...yes, and now it will also start it....till I drive it some where i guess.

Any way , I thought people would enjoy the true story.

So my basic problem is no comm

Help

tripleblackc5

I had the same thing happen to my 1999 C5 coupe while it was under the new car warranty (I bought the car new).

While driving in hot, humid weather with the a/c on, the a/c evaporator condensate drain line (a 90-degree rubber elbow) became clogged with white, grainy particles, and caused a/c condensation to back-up and not drain. The water overflowed from the evaporator case, and into the computer compartment in the passenger footwell (below the dash / glove compartment). The water followed the wiring harness and damaged the car's computer. The water "wicked" into the compartment, so the water overflowing was not readily noticeable.

All of the problems you described happened to my car - and included the horn began honking on and off. The car died while I was driving it, very close to a Chevrolet dealership (I was driving out-of-state, on vacation). A car salesman helped me push the car onto their lot and into the service department.

The car's computer had to be replaced and the evaporator drain tube cleared. The mechanic said he had seen several C5's with this problem. He believed the white grainy material was being shed from a coating on the a/c evaporator core.

Remove the floor mat and computer cover in the passenger footwell. See if the computer and/or wiring is wet. I suspect this may be the problem.

I hope this helps. Good luck.

[tripleblackc5]

Originally Posted by 1999 White C5 Coupe

I had the same thing happen to my 1999 C5 coupe while it was under the new car warranty (I bought the car new).

While driving in hot, humid weather with the a/c on, the a/c evaporator condensate drain line (a 90-degree rubber elbow) became clogged with white, grainy particles, and caused a/c condensation to back-up and not drain. The water overflowed from the evaporator case, and into the computer compartment in the passenger footwell (below the dash / glove compartment). The water followed the wiring harness and damaged the car's computer. The water "wicked" into the compartment, so the water overflowing was not readily noticeable.

All of the problems you described happened to my car - and included the horn began honking on and off. The car died while I was driving it, very close to a Chevrolet dealership (I was driving out-of-state, on vacation). A car salesman helped me push the car onto their lot and into the service department.

The car's computer had to be replaced and the evaporator drain tube cleared. The mechanic said he had seen several C5's with this problem. He believed the white grainy material was being shed from a coating on the a/c evaporator core.

Remove the floor mat and computer cover in the passenger footwell. See if the computer and/or wiring is wet. I suspect this may be the problem.

I hope this helps. Good luck.

You are so right!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!1

today..three days later, communciations are back and the car is working. Prior to this I had the top down and it rained............

Is there something that gets cloged up that causes the problem..
ever c5 owner needs the info, the computer will not fail from this but commications will....but the dealer doesnt care.

This is great we need to tell the world!!!

[1999 White C5 Coupe]

Originally Posted by tripleblackc5

You are so right!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!1

today..three days later, communciations are back and the car is working. Prior to this I had the top down and it rained............

Is there something that gets cloged up that causes the problem..
ever c5 owner needs the info, the computer will not fail from this but commications will....but the dealer doesnt care.

This is great we need to tell the world!!!

In my case, the 90-degree rubber elbow that protrudes from the firewall (at the rear of the passenger side engine head) became clogged and permitted a/c evaporator condensation to back-up and overflow into the computer compartment inside the passenger footwell. So much water entered the compartment that it ruined the computer. Perhaps if you had rain water enter the passenger compartment, some wicked into or entered the computer compartment in the passenger footwell.

It sounds as though your computer "dried out". If it was damp inside the computer compartment, I would ensure that the cover is left off and the area permitted to dry completely. Maybe even use a small fan to ensure it is completely dry.

If you believe the a/c drain is clogging, it can be removed and cleaned. Raise the right front of the car (use jack stands......) and with the engine completely cool, reach up from underneath and pull the rubber elbow from its mounting tip that protrudes through the firewall. Clean the inside of the drain. The drip end of it is molded into a small opening and is prone to clogging. You may want to cut-off the tip, to permit faster draining of the a/c condensation. Then replace the rubber elbow.

It is a tight fit to reach up and remove the drain elbow, thus the advice to do it with the engine competely cool. You can see the rubber elbow from above with a flashlight, but it can't be reached from above. Here is a link to a photo of the rubber elbow from below: http://www.c5forum.com/cgi-bin/ultim...64.html#000001

I hope this helps - good luck. It sounds as though your computer wasn't ruined (like mine was).

[vettex2]

I just used a coat hanger to poke the crap out

or cut the tip off