MrJimi1121

Had this issue twice now. Not sure what the heck it could be. While making a wot pull (TC OFF) right around 80mph the front ABS engages and nose dives the truck. Truck was in Auto and not manual. I did see the stabilitrak come on for a second. Truck has a level kit and stock wheels with 33' tires, the computer has been flashed for correct tire size. Truck also is turbo, stock pump and injectors. L86 throttle body and Manifold. It also has a snow performance progressive meth kit installed, signal wire to meth is tapped from MAF signal wire. My key on power source for gauge and meth kit is ran inside the truck to driver side fuse panel. There was a open spade (above the 50amp fuse). Truck has 31k miles on it.



I pulled the codes from the ABS computer
C0035 LF wheel speed sensor circuit malfunction
C0056 RF wheel speed sensor circuit malfunction
C0057 Yaw rate circuit malfunction
U0401 invalid data recieved from ECM/PCM "A"
U0101 Lost communication with TCM


I went over the wiring and found no rubs or issues. Also removed back dash panel and checked the two ground studs in the corners, seemed like it had a proper ground. Checked front hubs and seemed normal. When the issue happens no lights remain on, it just engage the front brakes and i feel like the throttle body closes. Slows me down to around 20mph.

Blue04SS

iTrader: (7)

I know what you mean. My truck does this when im turning with the Traction Control off as well. It sucks when you are pulling out in front of traffic! Id also like to know what the issue is.

FFDP

iTrader: (2)

I think part of the reason because of how the PCM/TCM and the ABS/BCM read vehicle speed. From what I understand the front tires are read through the abs system and the rear tires through the PCM/TCM. Without the ability to reprogram the BCM you end up with a fault. You can correct the speedo but you can't fix the other part of it. Seems to be mainly the stabilitrak that causes the problems when turning.

The older GEN 3 vehicles never seem to have this problem because of how simple the controllers were.

If you own a tuner try putting the stock tire size back into the computer and see what it does. The speedo will of course be off but see what it does for the ABS problem.

MrJimi1121

wasnt sure if anything in brake torque management would have an effect.

GR8TALK

Can you share the calibration file?

MrJimi1121

Here ya go.

smokeshow

iTrader: (16)

Without seeing data, it sounds like some intrusive torque security... Does it happen just over 5000rpm?

GR8TALK

Calibration seems good. I got a few ideas but wanted to make sure I understand what is going on. During a WOT pull at just about 80mph the truck loses all power from the engine and slows to about 20mph? Do you need to restart the truck to resolve this or does it resolve itself? I’m assuming this is an intermittent problem or does it do it every time you exceed the 80ish mph wall. I’ll wait for your response.

MrJimi1121

Has only happen twice so far. It only happen from a WOT pull. I recall both times being over or about 80mph. It feels like the front ABS engages and feel the throttle body close. The engine doesnt died, slows me down to about 20mph and then drives like normal. During the event i see the StabiliTrak light come on and go off. Hopefully this is detail enough.

smokeshow

iTrader: (16)

Better recheck that calibration... The torque model needs work. Doesn't need to be perfect, but it does need to not report 1000tq+ on the airmass surface as you approach the rev limit. Again, we need to see data.