tech2

what was their reasoning for now doing it? I could see not wanting to change tpms threshold pressures.
for older models that don't use gd2; It doesn't requiring programming...just a full function scan tool. Someone with a good snap on scanner can set it up.

mountainmanjoe

It was a while ago I don't remember exactly what they said. I wanted to progam my 2000 Astro AWD because I put taller tires on it. No TPMS.

Here in the nanny state of Canada everybody wants to decide for you what best/safest.

tech2

I hear you. My argument to them would be: trucks come with multiple rim and tire variations from the factory. As long as you have the correct rated tire...what is the safety concern?...then I would move on to another shop. If it was a legal liability for gm...they wouldn't make it accessible in the module for anyone with a scan tool to change.

Accurate vehicle speed input is not just for the odometer and speedometer but for correct transmission shifting. Wrong vss input will cause delayed/premature shift points.

mountainmanjoe

Well I may have to go through that again. I plan to put bigger tires on my Savana.

Yup and ABS activation too

SchnauzerKing

I just replaced my tires and wheels on my 2012 Express 3500 Passenger van. Originally LT245/75R16 Bridgestones (same tires found on the Flintstones car) mounted on those less than exciting grey steel wheels. White lettered Michelin's of the LT265's type. Found a set of very nice GM aluminum wheels on eBay. Along with five new TPMS tire valves. Yes I did the spare too. I wanted to have my diesel guy reset my computer for the larger tires but right now the tuners won't touch them around here due to the EPA cracking down. And I can't go to the dealer now because, well, I don't need a computer flash. Tires look great. I did notice if I turn really tight while backing in my drive with a sharp incline they rub.

tech2

what are the epa cracking down on? Changing tpms settings? Its not illegal to run different size tires and rims.

SchnauzerKing

No. Nothing to do with the tire/wheels. At least not directly. I have a diesel and some performance upgrades. That's the issue. The tuners won't touch it. The dealer will but the re-flash will cause me much heartburn. Not to mention lots of cash.

tech2

i'm not talking about changing module programming. Its not a flash. Changing tire size is selecting a different tire option that is already present in the factory module. It doesn't require a tuner just a scan tool.

SchnauzerKing

I wondered about that. I went back to the shop that did the work on the truck and they told me about the EPA and the horror stories from BullyDog. They told me to lay low for a while and do not go back to the dealer. My other local mechanic no longer has the scanner needed. He suggested the dealer as well but thought I would run into problems.

I do not understand this completely. You are saying there is a way to reset the tire size without effecting oh I don't know. Let's say a delete. Just for an example. If someone was to remove the DEF system for argument sake, not that I would, but let's say it had been. The program was changed to ignore certain sensors. Whatever module or system that controls tire sizes is different than that of the engine?

I would love to have my system calibrated to the larger tire size but I am afraid the dreaded 500 mile to total shutdown timer would kick in. Been there. Done that. And it is no fun.

Maybe the issue is LT265/75R16's are not an built in option, thus the rewrite. My service truck is an Express Cut-Away. It has LT225/75R16's. So I would say that would be a built in option.

mountainmanjoe

My dealer doesn’t want to program anything that wasn’t on the vehicle when it was sold. He wouldn’t let me upgrade the stereo. Something about being tied to the VIN. No deleting rear airbags even though I removed all benches and rails.