Can the MDI2 w/ AcDelco TDS EDIT parameters or just flash OEM updates?

Epsilon Plus · September 2, 2023

Greetings.

The long and short of what I'm trying to do is lower the TPMS threshold in the truck we all hate so the warning doesn't come on at 62psi or whatever. I have a cursory understanding of the GM MDI2 (and cheap clones) and using an ACDelco TDS subscription. However, everything I can find on the internet just shows people flashing complete write OE updates on to modules. There is some talk on forums of people having limited success having the dealer edit TPMS values, which tells me they must be using this software to do so.

Before I unload a bunch of money I'm wondering if anyone has had any success with editing values, not just flashing OE updates. I have yet to see any screenshots of anyone acutally playing with TPMS values other than with an uber-expensive Snap-on ModisUltra.

Bonus points if this MDI/TDS route can change tire size value too which would eliminate the need to buy a $250 inline "programmer" for larger tires.

Thanks!

newdude · September 3, 2023

10 hours ago, Epsilon Plus said:

Greetings.

The long and short of what I'm trying to do is lower the TPMS threshold in the truck we all hate so the warning doesn't come on at 62psi or whatever. I have a cursory understanding of the GM MDI2 (and cheap clones) and using an ACDelco TDS subscription. However, everything I can find on the internet just shows people flashing complete write OE updates on to modules. There is some talk on forums of people having limited success having the dealer edit TPMS values, which tells me they must be using this software to do so.

Before I unload a bunch of money I'm wondering if anyone has had any success with editing values, not just flashing OE updates. I have yet to see any screenshots of anyone acutally playing with TPMS values other than with an uber-expensive Snap-on ModisUltra.

Bonus points if this MDI/TDS route can change tire size value too which would eliminate the need to buy a $250 inline "programmer" for larger tires.

Thanks!

It can only be done with GM SPS2 programming. You'd have to perform a BCM setup (DISCLAIMER! AT YOUR OWN RISK!) and during the BCM setup you set the tire size and pressures based on the door placard. Or, in the case of changing the TPM threshold, the TPM threshold.

You cannot just go in to GM GDS2 diagnostics software and alter the parameters. Same with something like a high end scanner. Its not like Ford peoples and the FORSCAN program.

The tire size WILL NOT fix the ECM side of tire size programming. That requires an authorization code and VCI specific version of programming of the ECM and BCM, plus any camera modules if equipped, and its ONLY for factory size tire options.

carkhz316 · December 29, 2023

You don't need to program anything via TechLine Connect (SPS2) to lower the tire pressure threshold. It can be done via GDS2 (either a legitimate access) or via a VX Diag tool, or any capable aftermarket scan tool that can access tire pressure data. I did it on my '21 with a lower model Autel, but found later I could do it via my copy of GDS2 as well. I set them to the lowest (I believe 36 psi) and don't have any low tire pressure warnings running the tires down into the 40s.

Tire sizes, however, can only be programmed/ changed via HP Tuners or equivalent.

Edited December 29, 2023 by carkhz316

Epsilon Plus · January 21

Anyone know the meat & potatoes of how the Pulsar LT inline is correcting speedo/TPMS? Seems to me you need to talk to the BCM for TPMS and the ECM for size. Right now the most expensive path to correcting speedo is MDI/GDS2 access to the BCM for TPMS and HP Tuners for the ECM.

My real concern here is getting the speedo right for the odometer. I'm assuming if the speedo is off even by 1-2mph, the truck will be counting (or not counting) miles that aren't true messing with service intervals, resale...etc.

The Pulsar LT reportedly will correct tire size and allow TPMS threshold adjustments for ~$450, but I'm aware of GMs TSB about being mad about them and how they can cause errors (probably because you have to access 900 modules to do it right).

I'll be heading from stock Z-71 17x8s with 31s to Alaskan 18x8s with 35x11.5s. The only dealer way around this I can think of is if one had a 2024 they could use the ZR2 stock dealer calibration, but alas thats probably Global B stuff only and I have a 2022. I could argue with the dealer about giving me a stock cal for the 18s since they are an official GM accessory bought from the main site, but that's only 33s. EDIT: I just had a thought that since the Nittos I'm going with are 34.8" tall and the stock 20" option on these trucks is 34.1" so I guess I could use that factory cal?

Long and short of it, any ideas on the best or most affordable way to go from 17s & 31s to 18s & 35s and getting the speedo/odo right on the money?

Thanks.

Edited January 21 by Epsilon Plus

rjgvt · January 21

Picked up my 2024 2500HD AT4 three days ago and set the tire pressures to 60psi for all 4 tires. Haven’t received any TPMS errors yet. GMC app shows orange for the rear tires.

I have an Autel TS508 that I use to relearn the TPMS sensors when I swap wheels. It’s supposed to read the tire placard pressures and be able to change the placard readings for certain vehicles through the OBD2 connector. When I get a chance I’ll check if it works on my truck. I know it won’t help you with the tire size.