I'm just curious!

Where is our mileage stored, PCM or in the gauge cluster? Or both?

I'm getting the Granatelli 200 mph speedo, I have to send them my whole cluster. So, I assume it is where the mileage memory is since the PCM will be without power for a week or so.

 

I researched a bit and found the answer myself, according to GM reps anyway.
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Well, I spoke with XXXXXXX Pontiac, and 2 of my local dealers, as well as a Pontiac technician that I know.

Here's how it works.

The mileage is saved in the cluster ONLY. If you were to lose battery power for 30 minutes or more the PCM loses the reading. As soon as power is restored the PCM will retrieve it from the cluster. Simple as that.
If you order a new cluster, they will not give it to you until they burn your current mileage into it. They take your word for it mainly, but they will check NationWide to see what your mileage was the last time you had service or repair at a dealership. If you never have, it's what you tell them. They have no choice but to give you a new cluster. They will always request your old cluster, according to the people I spoke with. In my case I want a new one to send away for the 200mph speedo calibration from Granatelli Motorsports. I just would like to keep my original one in storage, like other parts that we like to keep. They simply said: what is your current mileage so we can order it with that mileage. Surely they'll check the dealerships first to see if it's correct.
A couple years ago a buddy of mine removed his and messed it up. He got pissed and slammed it, then threw it away. The dealership said they wanted his old one to get the mileage off of it. No can do, he said. He never visited a dealership so they had to take his word for it. They gave him a new one. GET IT!
So, I think I'm going to order a new one to send to Granatelli with my current mileage burned into the new cluster.

NOTE* FYI: Let's say your really fast and you can remove the old cluster and install the new one within the 30 minutes of power loss. And let's further say that the new cluster has "0" miles on it. But your real mileage from your old cluster had, oh, 26,847. If that 30 minutes hasen't elapsed, the PCM hasen't lost the 26,847 yet. It will then burn that into your new "0" mile cluster. The PCM and the cluster share info, they back each other up, but the PCM will only back up the cluster for 30 minutes. Just a little FYI, that's all, really.

Don't try this at home, leave it to the professionals.

 

[QUOTE]Originally posted by Ira:
[QB]That sounds really good, but I don't believe it's true. I don't think there is any way for the PCM to querry anything in the cluster and there is no reason the PCM needs to have the mileage. Changing the cluster is about 5 minutes, 10 at worst and you don't need to disconnect the battery if you're careful, just turn off the key. I have seen new clusters with zero mileage so I know they can be gotten that way.

Ira
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I would bet my hat that people have gotten new clusters with "0" mileage, but it is definitly where the mileage is stored. Granatelli won't even send you one without getting yours first, or a new one that the dealer has given you. The dealer said they will never give someone one with "0" miles on it. And further more, they won't even order it without knowing your mileage first so they can have the manufacturer burn it in.

 

FWIW, we import GM Camaro's and Trans Am's from USA to Australia. We have to put in an export (read Canadian) metric instrument cluster. We buy them brand new from a Chevy dealer, and they come with 'zero' on the odometer. We can also order them with correct mileage on them, also burned in. Have done it dozens of times. Only Chevrolet/GM/Pontiac do this, FWIW, Dodge want the core back and they burn in what it had in miles and translate that the kilometres... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

[QUOTE]Originally posted by Will Race 4 Food:
[QB]FWIW, we import GM Camaro's and Trans Am's from USA to Australia. We have to put in an export (read Canadian) metric instrument cluster. We buy them brand new from a Chevy dealer, and they come with 'zero' on the odometer. We can also order them with correct mileage on them, also burned in. Have done it dozens of times. Only Chevrolet/GM/Pontiac do this, FWIW, Dodge want the core back and they burn in what it had in miles and translate that the kilometres... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
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Being from another continent, I can see them selling them to you with "0" miles, laws mean nothing. It's just profit/business to them for those sales.

BTW, what does your car run in the 1/4? Nice set-up!

<small>[ May 22, 2002, 10:37 PM: Message edited by: Quickin ]</small>

 

That sounds really good, but I don't believe it's true. I don't think there is any way for the PCM to querry anything in the cluster and there is no reason the PCM needs to have the mileage. Changing the cluster is about 5 minutes, 10 at worst and you don't need to disconnect the battery if you're careful, just turn off the key. I have seen new clusters with zero mileage so I know they can be gotten that way.

Ira

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Quickin:
<strong>[QUOTE]Originally posted by Will Race 4 Food:
[QB]FWIW, we import GM Camaro's and Trans Am's from USA to Australia. We have to put in an export (read Canadian) metric instrument cluster. We buy them brand new from a Chevy dealer, and they come with 'zero' on the odometer. We can also order them with correct mileage on them, also burned in. Have done it dozens of times. Only Chevrolet/GM/Pontiac do this, FWIW, Dodge want the core back and they burn in what it had in miles and translate that the kilometres... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
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Being from another continent, I can see them selling them to you with "0" miles, laws mean nothing. It's just profit/business to them for those sales.

BTW, what does your car run in the 1/4? Nice set-up!</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">G'dday Quickin,
No, they don't care if we are from Australia or where-ever, they will sell to anyone. I've done it over the counter as well on trips to the USA and when I lived in LA. Give it a try, you'll get one easy!!

car is still inbuild stage, coming together nicely,looking for 10's on 346cid N/A, race car only. That should be straightforward....
Cheers <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />