This may be of help for those that have had a problem with the battery light that never turns off, even though you've replaced the battery/alternator/checked the grounds using a multimeter and it is still on.
Sometime last summer, the battery light turned on. Because of the heat here in Vegas, I usually get 22-26 months out of a battery, and get at least one replaced while under warranty before having to buy a new one. I would turn the car on, then off, and then on again and the battery light would clear. That worked for a few weeks, then the battery light just stayed on. I replaced the battery, but the light was still on, so I thought maybe the alternator. I replaced the alternator (it was stock, and 8 years was good enough for me), and the battery light was still on. So I used a multimeter and started checking the grounds under the hood. One had what I assumed was a bad ground, so I cleaned it and replaced it. No more wacky voltage numbers, but still battery light. I just resigned myself to believing it may be a ghost in the computer.
I started reading somewhere here about how there was a wire reporting to the PCM about the battery charging status, and to check that and see if the wire was faulty. I was going to ask which specific wire it was and ask how to check the wire (i assume burn off insulation and then use multimeter) but I never got around to it.
Fast forward to last week. Driving down the street and vehicle's engine stops. Stabilitrack warning light, CEL and the other engine light were on, and that pesky battery light was on. Pulled over to the side and tried starting it immediately, and it did not try to turn. Was going to call a tow and was going to use Onstar since my phone connection was no bueno, and I tried turning the car on. Car turned over so I drove over to a mechanic with only Battery and CEL on. Called Onstar while enroute and they said code P0601 - PCM Read Only Memory Error was pending. Took it to a shop and they said the same thing. So I called PCMofNC and they shipped me another PCM.
I plugged in the PCM and it started up. And much to my surprise, the Battery Light was off. Just need to get a CASE relearn completed now.
Not saying that the battery light staying on may be a sign the PCM is fading, but based on the other posts about their connection, seems a little more than a coincidence.
BTW I really appreciate all the information here and what used to be at the OS. I was not mechanically inclined before, but this has gotten me to become more adventurous, and saved me more than a heck of a lot of money by not going to a stealership.
Sometime last summer, the battery light turned on. Because of the heat here in Vegas, I usually get 22-26 months out of a battery, and get at least one replaced while under warranty before having to buy a new one. I would turn the car on, then off, and then on again and the battery light would clear. That worked for a few weeks, then the battery light just stayed on. I replaced the battery, but the light was still on, so I thought maybe the alternator. I replaced the alternator (it was stock, and 8 years was good enough for me), and the battery light was still on. So I used a multimeter and started checking the grounds under the hood. One had what I assumed was a bad ground, so I cleaned it and replaced it. No more wacky voltage numbers, but still battery light. I just resigned myself to believing it may be a ghost in the computer.
I started reading somewhere here about how there was a wire reporting to the PCM about the battery charging status, and to check that and see if the wire was faulty. I was going to ask which specific wire it was and ask how to check the wire (i assume burn off insulation and then use multimeter) but I never got around to it.
Fast forward to last week. Driving down the street and vehicle's engine stops. Stabilitrack warning light, CEL and the other engine light were on, and that pesky battery light was on. Pulled over to the side and tried starting it immediately, and it did not try to turn. Was going to call a tow and was going to use Onstar since my phone connection was no bueno, and I tried turning the car on. Car turned over so I drove over to a mechanic with only Battery and CEL on. Called Onstar while enroute and they said code P0601 - PCM Read Only Memory Error was pending. Took it to a shop and they said the same thing. So I called PCMofNC and they shipped me another PCM.
I plugged in the PCM and it started up. And much to my surprise, the Battery Light was off. Just need to get a CASE relearn completed now.
Not saying that the battery light staying on may be a sign the PCM is fading, but based on the other posts about their connection, seems a little more than a coincidence.
BTW I really appreciate all the information here and what used to be at the OS. I was not mechanically inclined before, but this has gotten me to become more adventurous, and saved me more than a heck of a lot of money by not going to a stealership.
