I've been having the following issues for about a month, and still don't have a solution. I'm posting in multiple forums to broaden the knowledge base I'm using to try and figure this out. Here's the problem ('04 CTT):


Start the car (it starts right up), then a series of warnings appear: Air suspension, brake proportioning, AWD failure, PSM failure, and PRND is either blanked out or highlighted (as if all gears are currently selected). During this time I can't move it out of park.

After idling for about 30 seconds, all the warnings clear on their own and the car is 100% perfect. No issues whatsoever.

So far I've replaced the battery (single battery CTT) and it didn't change anything. Durametric is showing errors in all the modules that I've listed, but all the errors are the same, "CAN Bus No signal/no communication." The only other code that is new is in the Vehicle Electrical section of Durametric. It is code 576 for Terminal 15 implausible signal.

When I clear the codes they all clear and do not return. If I restart the car and the failures appear, the same codes get set, and the cycle repeats.

The errors never return during a drive. Every time I start the car, I have a 50% chance of getting the errors. The other 50% of the time, no errors and everything is normal.

 

I would check for moisture in the electrical connections under the dash on the driver side floor. Which you are checking, you should probably check other areas as well.

 

+1 on this moisture is going to ceate shorts which these vehicles do not react well to. Each sensor has to see a certain impedence if this drops below that number it will create a short

 

OK, today I removed both front door sill trim pieces to look for moisture under the Left and right front seat carpets. Totally dry with no evidence that there had ever been moisture in the area. I looked under the carpets and under the padding. Dry. At this point I was actually hoping I'd find something wrong...

 

inspect where the drain tubes for the AC are, i've heard from other members this is where moisture occurs. Also inspect your battery cable, make sure it is connected tight and not loose and check the ground cable to make sure everything with both those cables are good, I would inspect both cables

 

I checked in the vicinity of where the A/C drain tubes leak too. That's the area under the front passenger floor (Left drive). Thanks for the tips, please keep them coming.

 

My tip is - you can chase this forever while an issue may, or may not, be damaging your car. Take it to the dealership (or your trusted mechanic) and let them diagnose, and/or fix, your car.

 

+1... If you have a Durametric, then hook it up and check for obvious errors and affected systems. If you not have one or this trail goes cold, then take it into a dealer or indy. These random issues can be a real nightmare to diagnosis on your own. This is where experience pays dividends.