2004 Lesabre speedometer erratic


bks81
10-20-2011, 10:35 PM
Hi all, I'm new to this forum, just havent needed any help till now. Anyhow, it seems I have joined the group of ya'll that have had a problem with the speedometer not showing the correct speed. It is buried to the right pretty much all the time, even when stopped and shut off. I see that the most common fix is to replace the instrument cluster or have it fixed. After many hours of internet research I have read that you can send them in to be fixed, or just buy new stepper motors and install them yourself. But I have also read that the PCM/ECM can have a bad ground. So I want to check that first, but I needed to know where the PCM/ECM is locate and the ground for it. I have also found a TSB that might address this, "06-08-45-004 MAY 06 Electrical - Instrument Panel & General Wiring Repair" , but can not find how to accually access and read it. So please feel free to reply with your input as I need to get this problem fixed.

Thanks,
Brian in IN
04 Lesabre

gmtech1
10-21-2011, 08:04 AM
The TSB is pretty much a generic bulliten outlining wiring repairs, not directly replated to your concern.
There is a splice pack bolted to the block under the ignition module, another splice pack on top of the trans along with a individual ground near this one.
From your description, the cluster will need repairs.

Tech II
10-21-2011, 06:09 PM
Are you saying that the needle is pegged against the stop? Can insert a wire to rotate the needle backwards...

Have seen this happen when people change a battery with the ignition on...

bks81
10-21-2011, 07:27 PM
No, the needle does move around some, but stays over by 140 alot.

Tech II
10-22-2011, 07:56 AM
Well, then we have to isolate the problem....

You need a scan tool, to read vehicle speed.....if the PCM is reading vehicle speed, then the VSS sensor is ok....Then you probably need a cluster....

If the PCM is not reading vehicle speed, then then VSS circuit and sensor have to be checked out....

dpalomaki
10-22-2011, 08:14 AM
See response in the LeSabre forum at

bks81
10-23-2011, 08:46 AM
OK, I now am confused. The car is the wifes car for the most part and she drives it daily. She has been telling me of the problems I have posted here. But yesterday I drove the car as I needed to drive 200-300 miles and didnt want to take my gas sucking truck. I of course hit memory 2 which is set for me, and drove the car for my trip. And the speedometer worked perfect for me all day. The problem I have with the memory seat is it will act like it puts the seat in my position, but once I get in, I can tell it doesnt move the seat back far enough, so I have to finish moving it back manually with the seat position button. The mirrors, radio and climate control all seem to be fine when switching from memory 1 to memory 2, or vice versa, but the seat will not move forward or back enough for where we have set the memory at. Anyhow, with this in mind, do the stepper motors act up for a week at a time then work fine for a time?? Or is the problem something else? And seeing how the cruise works when the speedo doesnt, that says the VSS is good doesnt it?

Thanks,
Brian in IN

bks81
10-23-2011, 09:00 AM
OH and I did think that maybe the speedo just has problems in Memory 1 position, so when I was stopped I hit memory 1 and drove the car a little while all cramped up and the speedo still worked fine. Then I went back to Memory 2 and it still worked. Someone mentioned weather related problems, it has been cold and rainy here most of the week, but yesterday was dry and in the 60's. My experience with erratic problems is normally bad connections of some sort. So the ground problem on the PCM/ECM seems appropriate for this problem. Can someone tell me where this ground is so I can elimiate that as the culprit??



Thanks,

Brian in IN

Tech II
10-23-2011, 10:06 AM
Tend to doubt it's a PCM ground problem......when the speedometer acts up, have you tried whacking the top of the dash with the palm of your hand? Has the vehicle been scanned for codes?

Most PCM grounds are located on the studs on the tranny(these are the bolts/studs that hold the tranny to the block)....

As far as the memory seat position, are you using her keys? When you use her fob, it remembers her position....

Have you tried to reset memory position 2, and then tried it?

dpalomaki
10-23-2011, 03:28 PM
Anyhow, with this in mind, do the stepper motors act up for a week at a time then work fine for a time??

Mine acted up mainly in summer, but usually after a bit of a drive drive. stopping the car and engine and restarting would allow them to start working again, for a while, and the problem MIGHT happen again in 10-20 minutes. The next day it might be OK all day, or it might start after 15 minutes, or after 2 hours, or not at all.

Again, mine tended to read LOW speed.

Replaced the stepper in late June and no issues since then. However, YMMV.

This is basically a $2 part in bulk. It is not a precise device, made in China, and mostly plastic/nylon. I suspect they wear a bit and then start to act intermittent based on internal temperature and perhaps humidity.

If everything else that is based on vehicle and engine speed and the gauge cluster grounds works OK, I would say the stepper is the prime suspect.

bks81
10-23-2011, 07:41 PM
Tend to doubt it's a PCM ground problem......when the speedometer acts up, have you tried whacking the top of the dash with the palm of your hand? Has the vehicle been scanned for codes?

Most PCM grounds are located on the studs on the tranny(these are the bolts/studs that hold the tranny to the block)....

As far as the memory seat position, are you using her keys? When you use her fob, it remembers her position....

Have you tried to reset memory position 2, and then tried it?

I have not scanned for codes, no service light has come on. I have tried whacking the dash, it does nothing.
I use my key fob or the #2 seat memory button on the door. We both have tried resetting the memory button many times, it double beeps like it should, but then still gives us the same results.
Just so you know, I have owned a 2000 park avenue and this lesabre over the last 11 years. I traded the P.A. in on this lesabre cause the PA had 151k miles on it and the lesabre had 42k, I just wanted to be sure the wife had a dependable car. I'm beginning to think I should have kept the PA. :rolleyes:
This lesabre has had problems since we got it, but nothing major. I dont know if I should post it here or in another thread. But it has always used 1-2 qts of oil in the time the car tells me its time for an oil change, where I never had to add oil to the PA in between changes. The climate control does not seem to keep the insdie temp as consistant as the PA did. Then the seat memory thing and this speedo thing. uuuggggghhhhh !!!!

Thanks,
Brian in IN

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