Crazy Electrical Stuff !!
Thread Starter
Le Mans Master
Joined: Sep 2000
Posts: 6,098
Likes: 43
From: ABQ NM
Cruise-In II Veteran
Crazy Electrical Stuff !!
Sorry this is a bit long.... I know the battery in my '02 was getting weak, such that I normally keep a battery maintainer on it. Due to circumstances, I didn't have it hooked up for the last several days. Went to drive the car this morning and it turned over - barely, and I drove it for several miles. Normally this has been enough to give the battery some juice. I stopped for about a half hour, and when I went to leave... nothing! Absolutely nothing - no lights, no power door locks, no clicking starter solenoid - it was as though a battery cable was disconnected (I checked and they were tight). Fortunately, where I had stopped, I was able to access a commercial-style battery charger, hooked it up, lights flickered, and then the car fired right up. Now here's where it gets weird. I have had the dreaded 1214 code (service ABS, traction control, active handling) issue for awhile. Initially it was intermittent, but for the last few months it has been constant. I've been putting off having the module repaired (ABSfixer or similar) until I resolve some other matters. So anyway, when I fired up the car, I realized that the warning lights were not lit. Drove it home... still no lights. When I had no traffic behind me, I got on the brakes (three times) hard enough to activate the ABS, and sure enough, they did (confirmed by the DIC readout) ! So is this purely a coincidence, or ??????????? I find it hard to believe the module cured itself, but I guess stranger things have happened. I put the maintainer back on the car and will have to see if this "fix" continues (plus I need to pull the codes and see if anything is different there). In the meantime, any of you electrical gurus care to make an educated guess as to what happened? I'm wondering if the charging and brief light flickering somehow jolted a relay or relays in the module, getting them to work. It's all 
to me !
to me !
Melting Slicks
Joined: Sep 2011
Posts: 2,258
Likes: 543
From: Appleton WI
I agree. Get a new battery. Your alternator will appreciate it to.
People don't realize that the longer you keep using a weak battery the shorter your alternator will live because it has to work harder. Think you have electrical issues now, wait till you put a new alternator in that the car doesn't like.
People don't realize that the longer you keep using a weak battery the shorter your alternator will live because it has to work harder. Think you have electrical issues now, wait till you put a new alternator in that the car doesn't like.
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
All C5's are exceptionally sensitive to low or weak batteries. So keep driving with the weak or bad battery and anything can and will happen. Most of the elecronics systems in the C5 run diagnostics when the key is turned to the ON position. If battery voltage at key ON time is low enough to have the diagnostics fail it is unpredictable what codes you will see or what symptoms you may experience. Having voltage AFTER the car is running and the alternator is producing a charge is TOO LATE to affect the diagnostics as they have already run. Often when the diagnostics fail the associated system will be disabled. For example if the EBCM diagnostic fails the ABS system can be disabled and invalid codes such as C1214 can be set.
My suggestion if to stop F'ing with the bad battery and replace it and most of your symptoms will likely go away.
My suggestion if to stop F'ing with the bad battery and replace it and most of your symptoms will likely go away.
Bill
