Car Going Haywire! Help....

Well this is my first post and i need some help.

Ill try and explain everything that happend so maybe someone could give me a good idea of what 'might' be wrong.

So last night im driving home and my traction controll light comes on saying to check it. Then the Radio turns off and as i pulled up in a parking lot to turn the car off and try and restart it it acts like the battery is dead. Hard to start, and wouldnt start actually. Then i wait a minute and try again. It starts right up but i still have the warning lights and the radio wont turn on. So as im driving home, the lights turn off then back on , the seatbelt warning light turns on and the the lights in the instrument cluster go off. Basically , its crazy I think.

So this morning i decide to see if it will crank up. And sure enough it cranks right up. No problems it seems. Couse i wasnt going to drive it but hell , i dont know what the deal is. I would think if it were the battery then it wouldnt have cranked back up, but ill let the diagnostics up to you guys or a mechanic of course.

Thanks in advance
Darrell

Whoa...

My first thought is front electronics module (FEM). I understand that troubleshooting an elctrical problem in the LS is a nightmare. Lou (Quik LS) might have a better idea of what's happening here. I've never had to dig into the electronics.

can you get it to an autozone? They can use their obdII scan tool to pull code from the pcm. Are you the original owner? If not did you pull a carfax.com report on it before you bought it? It could be an electrical fault, maybe a cable has lost its insulators from chaffing, bad FEM or REM.

The car uses a multiplexed bus so it only takes one bad component sending out of band data to make this Lovely Sedan, aka LS, go bonkers.

can you get it to an autozone? They can use their obdII scan tool to pull code from the pcm. Are you the original owner? If not did you pull a carfax.com report on it before you bought it? It could be an electrical fault, maybe a cable has lost its insulators from chaffing, bad FEM or REM.

The car uses a multiplexed bus so it only takes one bad component sending out of band data to make this Lovely Sedan, aka LS, go bonkers.


Any idea how much a computer might cost for this ?

checkfordpartsonline.com they will need your VIN in order to match it to the model you have. IIRC there is a Canadian PCM, Calfornian and Federal. I think they are around 1k dollars and it is something the dealer may have to install due to the multiplexed bus and trust established between the gauge cluster, rem, fem and pcm.

good luck.

I seriously doubt it's the PCM. Traction control should be driven by the ABS computer and radio functions are handled by the radio itself or in combination with the FEM. Almost sounds like an intermittent ground to me.

Regardless, I think you've got a long row to hoe. Good luck!

Actually, it tured out to be the Alternator. I suppose the low power made everything go crazy. So now everything is fine, but the alternator they put in makeing a whineing noise, so i have to take it back up there monday. I suppose they will have to put another in.. what a pain..

same exact thing happened to me about a month ago

I'm having the same problem... My instrument cluster has flickered a few times in the last week. Thought it was just me, then i noticed it began happening more often in the last two days. Last night when I hit the brakes the abs light came on, the radio was going off and on, the traction control light check came on and off and when I parked it wouldn't start. Grabbed my powerpack and jumped it, started right up today. The power pack showed the alternator was charging (14 volts). I decided to drive it home cause it seemed ok, 2 minutes into the drive everything acted up like the night prior. I had to throw it in neutral to keep it running. Almost felt like a pully was seizing up and basically stopping the motor from turning. Since the s-belt was fine I know this can't be the case, so I am hoping its the altenator. (The battery is only six months old) When I check the car status, it says "charging system ok", and I have no service engine idiot lights on nor any codes in the computer which I find strange since the car won't turn over cause my battery is drained... (btw, I own a 2002 LS V8, guess I should of mentioned that first) Should I roll the dice and put in a new altenator? Any help would be greatly appreciated...

Forum rules would suggest I discourage you from posting to a thread that is 5 years old, but I appreciate that you first searched the forum for existing threads.

I wouldn't go the route of a new alternator yet. I'd suggest you first determine where the current draw is, and don't rule out a bad battery just because it's pretty new.

You'll need to hook up a current meter in series with the battery and leave it there with the trunk open for a few minutes prior to noting the current draw. Wait until the interior lights go out. Since you appear to have a pretty decent load, you'll probably see a few amps of current draw. Then pull fuses in the rear fuse block near the battery one at a time to see if any one in particular causes the current draw to drop. If you pull one that causes the draw to go less than 1 amp you've probably found the circuit to focus your attention on.

My recall is the acceptable "stand by" current draw is around 70 mA, but that is after all the electronics are given time to go to sleep mode, something like 2 hours. And as soon as you start pulling and replacing fuses the components will no longer be in sleep mode so you might expect a current draw of around 700 mA.

-Rod

I would start with a check for loose wires. Start with the battery cables, then try all the main electrical junctions. Your's wouldn't be the first LS with loose wiring issues.
A drain on the battery wouldn't explain the issues you're having while the engine is running.
I don't think that it is the battery, because it is still starting the car (I assume without having to charge it.) For the same reason, the alternator is unlikely, but not impossible.

You might pick up one of those voltmeters that plug into the cigarette lighter and drive around with that and see what the voltage is doing. It should be between 13.8 and 14.5 volts while the engine is on. It will decay down to 12.6 volts with the engine off. While starting, it shouldn't go below 9 volts.

I had Check Charging System warnings. Replaced the alternator with no change in the voltage spikes (15+). We discovered that the cables between the battery and the rear fuse box were loose at the fuse box connection. When you pulled on them, all of the symptoms you described occurred. I had the bolt tightened where the cables connect to the fuse box and have not had any issues since.

it was the altenator... and I paid to have it put in, It looked like a pain to remove and install... thx for the suggestions though.

Thank you for the follow-up post, that's what helps to make these forums effective!

-Rod