92 lesabre electrical?

Hey guys (and gals), today I was stuck in traffic (like any other day) and when I stepped on the brake and let go, the car bucked almost as if I broke a spring in the pass side rear drum. It did it again and the ABS warning light came on. Very shortly after that, the ABS light went off and the Security light came on. Very shortly after that, the speedo needle jumped to 100mph and back down to <10mph (actual speed) and the Security light went out and for the rest of my commute everything was fine. Drive back home was fine, car starts and runs Ok but, I'm wondering what the hell that was all about to see if I can excersice a little preventitive maint. versus awaiting a total breakdown.
I hate and suck at automotive electrical so any suggestion, I hope will come with exacting details and directions ..... yea I suck that bad.

I'd love to give you a hand on this one. Unfortunately, unless you believe in gnomes and goblins, it has to do it again, more consistantly, or leave a telltale ABS/Service Engine Light for me to point you in any given direction.
Electrical is always a good time to track down.

If your ABS light came on, there might be a history code stored that can be extracted. If anything, check battery terminal tightness, and power distribution/ground straps. Near the battery, underneath a plastic cover/behind washer fluid bottle should be a tower with grounds and another with fusible links.

Good luck, and keep us posted.

Sounds like the PCM is starting to get a little freaky..........

My first thought was that I am losing ground at the battery because about a year ago, I stripped the bolt in the side post. Managed to get a tight enough connect to establish a circuit and vowed never to mess with it again. I dared to check it and both posts are tight. I also check the grounds by the battery and the fusible ground by the radiator overflow tank.
My battery is in it's 7th year after being drained 5 times on separate occassions, to the point it wouldn't light up the dome light (Interstate - the only battery I'll ever buy!).
Tomorrow, I'll extract the ECM codes and let you know what I find.
Hope this doesn't turn ugly and develop into one of those :banghead: situations.

scanned for trouble codes and it is not storing any faults.

Any ideas?

Hasn't done it since but, something caused and I can't rest until I find it. :banghead:

I had my spedometer do that during bucking.. actually the speedometer starts jumping very lightly before the catastrphic bucking.... Turned out to be a CRANKsaft sensor..

Good luck. Difficulty.. 3 of 5 .. need a impact driver.

had the crank sensor replaced a few years ago and didn't act anything like this. I recall feeling an actual physical buck out of the rear brake as if a spring broke or something. Of course my lazy azz hasn't bothered to pull the tire to see if anything strange is happening in there.

If your lazy azz is like mine it is waiting for inspiration overwhelm me enough to take a peek at the possibilities. Thinking of it logically from your text, the PCM is feeding your speedometer off the VSS. Sounds like the PCM fainted and could cause most of these symptoms. It seems to have restarted through the cycle of all the way back from the security check on up. I have heard of ignition switch areas make similar troubles and suspect a source voltage or grounding loss.



Good luck

Today on the way home, I had someone kindly inform me that I had no brake lights. Got it home and verified this to be true. No hazarads either. The whole time I'm thinking about having to take a day off and bend over for the elec. shop.
Well, I checked the fuse and it was good. Just by chance, I pulled an equal amp fuse and switched the two. Cool, brake lights are back in action. Thinking this was too easy, I double checked the original fuse with a voltmeter and found it to be good. Turns out some corrosion had built up and it stop conducting juice. Pulled all my fuses, shined them up with emery cloth, coated them with dielectric grease and reinstalled. Not sure if this has anything to do with my original problem but, it sure isn't going to hurt anything.

Wait a minute, do I even have a PCM on a 92'?

yep