PCM & Odometer
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From: Cincinnati Area
PCM & Odometer If you put together a PCM from one car and a dash cluster from another, what will happen to the mileage on the odometer?
In other words, if I put a pcm from a car with 50K miles in a car with 25K miles, does the pcm log the mileage or is that only recorded in the odometer?
Hope the question makes sense.
In other words, if I put a pcm from a car with 50K miles in a car with 25K miles, does the pcm log the mileage or is that only recorded in the odometer?
Hope the question makes sense.
Last edited by kenp; Feb 7, 2006 at 10:37 PM. Reason: spelling
Im not sure if the PCM logs milage or not...I dont think that it does, and I base that off of the fact that Ive never heard anyone mention it...if it does then I dont think that anyone has "Cracked" that part of the coding yet.
To answer the other part of your question though....using your example of a PCM with 50K in a car with a dash cluster with 25K on the clock....the dash cluster will display 25K...and count up from there.
Im sure that there is a way to "even" the two up
but I doubt that any of the tuners would attempt something like that due to legal "issues"
Hope this helps
FWIW...I went through this with my 97 Camaro swap 2 years ago....it was a V6...
To answer the other part of your question though....using your example of a PCM with 50K in a car with a dash cluster with 25K on the clock....the dash cluster will display 25K...and count up from there.
Im sure that there is a way to "even" the two up
but I doubt that any of the tuners would attempt something like that due to legal "issues"Hope this helps
FWIW...I went through this with my 97 Camaro swap 2 years ago....it was a V6...
That is correct, but the PCM will also keep going up in mileage. I have heard that it does store mileage, but it may not referrence the odometer reading. The PCM give the odometer the mileage to add. I don't know of any tuning program that can legally access it, beside (and probably not) Tech-II.
TECH Senior Member
Joined: Nov 2001
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From: Lake Zurich, IL
I haven't heard positive one way or the other about the PCM storing mileage... I do know that the Odometer is fed off the speedometer... so if hte PCM stores mileage also, it doesn't talk to the odometer on any updates...
I believe if you get a new cluster from GM, they have the ability to reprogram the Odometer to the proper mileage, however if you're using a different odometer, I think it'll keep whatever mileage was previously in that gauge cluster and count up from there....
I believe if you get a new cluster from GM, they have the ability to reprogram the Odometer to the proper mileage, however if you're using a different odometer, I think it'll keep whatever mileage was previously in that gauge cluster and count up from there....
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
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From: Lake Zurich, IL
changing the PCM definetly 100% doesn't effect the mileage reported on the odometer.... I've had quite a few different PCMs in my car and never had a problem w/the reported mileage.
(though the PCM can affect the odometer if the tire size/gearing is wrong, in which case the Speedometer is wrong, which causes the odometer to count wrong)
(though the PCM can affect the odometer if the tire size/gearing is wrong, in which case the Speedometer is wrong, which causes the odometer to count wrong)
