Gauge Cluster question

**SteveCZ28** · 06-15-2011, 10:36 PM

Im curious about replacing gauge clusters...if i were to replace mine with a different cluster, would the new clusters mileage be my "new" mileage? or does the mileage actually stay the same as my car?? im just curious as i want a 2nd gauge cluster to do some overlays on, and dont wanna mess up my stock/factory cluster

**az gt eater** · 06-16-2011, 04:09 AM

The cluster holds the mileage.

**98TransAmWs-6** · 06-16-2011, 08:09 AM

Originally Posted by az gt eater

The cluster holds the mileage.

The mileage is calculated by the computer. So a new cluster shouldn't have any effect on that.

**SteveCZ28** · 06-16-2011, 10:07 AM

lol what is it guys? i have 2 replies, and 2 differen answers

**98TransAmWs-6** · 06-16-2011, 11:34 AM

This should help clear up anyone who doesn't understand how they work:

Digital odometers use a toothed wheel mounted to the output of the transmission and a magnetic sensor that counts the pulses as each tooth of the wheel goes by. Some cars use a slotted wheel and an optical pickup, like a computer mouse does. The computer in the car knows how much distance the car travels with each pulse, and uses this to update the odometer reading.

If needed I can go into more detail about they work but hopefully this explains it enough.

**az gt eater** · 06-16-2011, 11:45 AM

Changed your cluster out? Or is this theory? I've changed mine.

**JayTA98** · 06-16-2011, 03:26 PM

the computer keeps the mileage. If you swap the clusters it will show the current mileage from the PCM.

**98TransAmWs-6** · 06-16-2011, 03:39 PM

Originally Posted by az gt eater

Changed your cluster out? Or is this theory? I've changed mine.

If it reset for you I think you didn't do something right. Mechanical odometers have the mileage stored in the cluster. Digital odometers just reflect what the computer tells it. It's not theory it's fact.

**SteveCZ28** · 06-16-2011, 09:59 PM

so if i swapped a pcm out, my mileage would be whats on that pcm????

**666ws6** · 06-17-2011, 03:22 AM

I don't think mileage is in the PCM, it must be in some other controller. I've swapped my PCM many times, never had any odo changes.

Interested to hear from others on this, I'm curious now too.

**KMdef9** · 06-17-2011, 05:49 AM

Originally Posted by 98TransAmWs-6

This should help clear up anyone who doesn't understand how they work:

Digital odometers use a toothed wheel mounted to the output of the transmission and a magnetic sensor that counts the pulses as each tooth of the wheel goes by. Some cars use a slotted wheel and an optical pickup, like a computer mouse does. The computer in the car knows how much distance the car travels with each pulse, and uses this to update the odometer reading.

If needed I can go into more detail about they work but hopefully this explains it enough.

Yup, it's also how ABS and traction control work.

Originally Posted by 666ws6

I don't think mileage is in the PCM, it must be in some other controller. I've swapped my PCM many times, never had any odo changes.

Interested to hear from others on this, I'm curious now too.

Wouldn't shock me if it's a hidden module, so it isn't so easy to "lower" your mileage.

**jiveass** · 06-17-2011, 06:09 AM

i believe its a team effort between the pcm and the computer thats in the cluster....if it was purely the pcm, the odometer would change if you swapped pcm...theres probably a few other things in the mix that will correspond with the info too..

**SteveCZ28** · 06-26-2011, 11:46 AM

well being as i couldnt get a clear straight forward answer from anyone, i went ahead and asked a buddy of mine of whom has another camaro. i pulled his gauge cluster, and mine, and swapped....hear is the answer i was looking for:

the gauge cluster holds the mileage.
example: if you swap out a gauge cluster from a car that say has 129k, and put it in your car, your car will now read 129k.....

so yea, now that is out there, and maybe someone can read this and have a for sure answer....now i can buy another gauge cluster to put my overlays in and not have to worry

**az gt eater** · 06-27-2011, 08:13 PM

I spoke from experience. Thanks for the update.

**SteveCZ28** · 06-27-2011, 11:28 PM

yea i wasnt believing anything anyone was saying as there were too many different answers. so i fugured the only way to find out is try...glad i did. now i can move forward lol

**JayTA98** · 06-28-2011, 05:57 PM

I spoke from other experiences from other cars but never from this one. So I was wrong and I learned something new today from you guys. Thanks for the update as well. I'm glad that you actually tried yourself and got the answer that you were looking for. Good job.

**Mr_Rich** · 06-29-2011, 12:24 PM

I think I remember accessing my ECM with Autotap and the mileage shows up there. I would think that the instrument panel would be subordinate to the ECM.

**JayTA98** · 06-29-2011, 12:28 PM

Originally Posted by Mr_Rich

I think I remember accessing my ECM with Autotap and the mileage shows up there. I would think that the instrument panel would be subordinate to the ECM.

thats what my knowledge has been but the OP just swap it out and confirmed the mileage followed the cluster... I never done it in our cars. it doesnt make sense from what I know but again I never done it so I have to give it the benefit of the doubt when someone tell us that he just did it.

**Cutlass** · 07-01-2011, 02:41 AM

Yep. Miles is stored in the cluster on an F-body. To keep the correct miles reading, you'd have to go through a GM authorized electronics rebuilder.

**chuckie669** · 07-01-2011, 10:37 AM

My pickup truck cluster failed. Sent it to a speedo repair place in florida and he reprogrammed the cluster with the mileage that was off the broken chip memory.