cold start??? WTF?
Thread Starter
Burning Brakes
Joined: Apr 2006
Posts: 833
Likes: 1
From: long island NY
St. Jude Donor '06
cold start??? WTF?
This just started on saturday night... when it is cold out my bcm just goes absolutely insane... and fails every system that it runs, the problem goes away after I warm it up and recycle power.... This happens to me all of the time in the aviation world, and I figure that the same holds true for these cars, and it is just the cold that is messing with the computers and that once I warm them up and cycle power to them all is fine. 
Or do I have another problem looming?
Or do I have another problem looming?
Le Mans Master
Joined: Sep 2003
Posts: 8,847
Likes: 795
From: Longview Texas
My battery is fully charged, and everytime my car sets in cold weather very long, I get Service Active Handlling and sometimes a couple of other stray error codes. After the car warms up, all the codes clear after one ignition cycle. I am also wondering if there is anything I can do to keep the cold from messing with the electronics.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
BCM on C5's get exposed to moisture if there are any passengers foot well leaks or if the HVAC air box drain gets plugged. I would see if there is any signs of moisture in the foot well, Check the carpet underlayment and see if it was/is damp. I would see if you can get your arm as far back under the seat as possible as the moisture has a tendency to settle under the passengers seat area. Even check from the rear of the seat. My BCM in my 98 corroded from moisture and died. i had to end up replacing it with a new one. It had corrosion on the circuit board that i was able to remove once!
You can open the BCM box and check the underside of the board for moisture/corrosion.
You can also use a hair dryer and warm up the BCM then start the car COLD and see if the problem still exists.
BC
You can open the BCM box and check the underside of the board for moisture/corrosion.
You can also use a hair dryer and warm up the BCM then start the car COLD and see if the problem still exists.
BC
