Changed tire size on my 08 cc 2500 AND..

08hunter2 · 03-05-2008, 07:24 PM

Changed tire sizes on my new truck & can't get the tire pressure monitor light to go out. The stock tires call for 80 PSI. The Mud Terrains I put on only run 60 psi. Dealer said they can't reprogram it. Seems like they could. Also does anyone know if the dealer can reprogram the speedometer & tranny shift points after tire changes? My dealer again says no. I find this hard to believe, any input appreciated.

codyt · 03-05-2008, 07:41 PM

I believe that the dealer should, be able to change speedo and tranny shift points with a Tech 2. As for the tire light when i used to work at a chevy dealer, we could only reset and turn off lights not reprogram. but im not positive about this so you might wanna check in with another dealer.

**Tow Master** · 03-05-2008, 11:57 PM

Id have to say that the dealer should be able to recalculate your tire pressure sensors but cant do the shift points and speedo change. I think the dealer can only program something back to stock but not adjust something.

To adjust the speedo and shift points Id pick up a cheap programmer such as Hypertech, Diablo, or PPE. They'll have the ability to adjust and add some extra power

gawettla · 03-06-2008, 04:47 AM

I have a 2007.5 2500HD, and my dealer reprogrammed the tire sensors in the rear from 80 to 60psi. The fronts were already at 60psi.

I have been running my tires at around 55 psi with no tire pressure warning lights.

TheDuke · 03-06-2008, 07:52 AM

What Gives ?

I have 35 inch tires and that damn light is ALWAYS ON !!

Went to the Dealer and they said they can't turn off or change the pressure sensor.

Are you saying they can ?

gawettla · 03-06-2008, 09:05 AM

Yes they can

I ran my tires at 55lbs for months and the light was always on.
When I brought it in for service, I asked them to change it. They asked me what pressure I wanted it set at, I said 60lbs.

Incidentally, I have the stock 245/75/16 E tires. They have a weight rating of about 3000 lbs each at 80 psi. The truck has a front GAWR of 4500lbs and a rear GAWR of 6000 lbs. So the door sticker says front tires at 60psi and rear tires at 80psi. This is at what the TPMS is set.

The actual weight of my truck empty is about 4200lbs front and 2400lbs rear. So the correct tire pressure for an empty truck is 56psi front and 32psi rear with those tires.

I have a jeep with larger than stock tires, and I run them at about 18lbs all the time.

TheDuke · 03-06-2008, 09:40 AM

Calling my buddy right now at the Dealer and telling him what I said, I will get back to ya

TheDuke · 03-06-2008, 09:49 AM

Ok,

He said they can Adjust to go UP, but he can't changed it to go DOWN, which is what I need.

22 inch Rims on 35's is a ROUGH RIDIN SOB at 60 lbs. of pressure.

I run them at 50 Max for a smooth ride.

**Tow Master** · 03-06-2008, 11:05 AM

Quote:

Originally Posted by TheDuke

22 inch Rims on 35's is a ROUGH RIDIN SOB at 60 lbs. of pressure.

I run them at 50 Max for a smooth ride.

But, Youll get better MPG's at 60

TheDuke · 03-06-2008, 12:08 PM

Quote:

Originally Posted by Tow Master

But, Youll get better MPG's at 60

Ya but do you think it will be that much better ?