Strange issues with Duramax

[Jtyson]

Alright this might be a little lengthy, but I want to be thorough explaining everything so I can hopefully figure out whats wrong. I am working with two 2008 Silverado LMM Duramaxes. One is an ECSB 2500hd the other is a CCLB 3500hd. They have identical mods (same owner), both are 4x4, they are pretty much the same truck as far as everything goes. I am installing the same set of DSP5 tunes on both trucks. I didn't build the tunes, Rob Coddens @ATP was who put them together for me. I do all the flashing and scanning and installation.

I don't have any issues with the tunes working, all of them work great and switch correctly. However, on BOTH trucks, on all tunes beside the stock (base) tune, if you get on it at all, the ABS, parking brake, and service trailer brakes lights all come on. If you pull over, switch back to the stock tune, turn the truck off and back on, it goes back to normal.

These are my buddy's trucks and he has gone through hell with the GM dealers for months thinking that some body module must be screwing it up, or an issue with tire pressure sensors or brake sensors or something. He has replaced everything twice on the ECSB 2500. He just recently got the CCLB 3500 though, and while he was waiting for his DSP5 switch to come in the mail, he was using a Quadzilla Stealth II on the truck. He had NO issues with the service ABS lights, trailer brakes, etc until I installed the EFI Live last night. So obviously this problem is within the tuning somehow. I just need to find out where and what I need to do to fix it.

I appreciate any insight anyone may have!

[Dmaxink]

I know if you set the tire size above 35" it will do that, but if the speedo hasnt been tampered with since rob sent you guys the tunes i wouldnt think that would be it. Have you guys contacted rob on this?

Thanks

[Jtyson]

I know if you set the tire size above 35" it will do that, but if the speedo hasnt been tampered with since rob sent you guys the tunes i wouldnt think that would be it. Have you guys contacted rob on this?

Thanks

I have the tire size set at 34.75" - could that be doing it? I have had to adjust the speedo calibrations a couple times for different tires, but never has gone above 35"

I have emailed Rob, just waiting for his response.

[Dmaxink]

For kicks try putting stock values in the speedometer calibrations and see what you get