Pressing Brake Triggers Open Loop

[axekick]

I have a descent handful of tunes under my belt but this is something I haven't seen before. The vehicle is a 2002 Trailblazer that has been converted from the straight 5 or whatever to an LS1 and runs off of a 98 PCM, I think the PCM is from a camaro. Anyway, this truck goes into open loop anytime its in gear and the brake pedal is depressed. It stays in closed loop if its in park and you push the pedal and goes back into open loop immediately when the pedal is released. So to summarize

In park - brake not applied - closed loop
In park - brake applied - closed loop
In drive - brake not applied - closed loop
In drive - brake applied - open loop

Is there something in the tune that controls this that I'm not aware of?

[FMX05]

Did you ever figure this out? I have a 99 Silverado doing the same exact thing. I've done around 100 tunes and this is a first for me. I've found 3 or 4 other threads about this same issue and no one ever came up with an answer.

[VPU1320]

well sorry to bring this back from the dead but anyone figure it out? im tuning a 99 camaro with a 408 and a 4L80 and its doing the same exact issue. put it in gear with no brake and stays in closed loop. barely touch the brake and goes to open loop. this one however stays in closed loop if i hit the brake in park and neutral. but its really stumping me.

[95solster]

Can you post your tune file please

[95solster]

Try this.

Using HP Tuners: Under "System">General>System Options, Under Brake TqMgt, and your platform, it must = zero. If you don't know which is your platform, look it up just above the system options button or make sure they're all set to 0.

Then YOU MUST DO A WRITE ENTIRE and then boom, it'll be turned off, you'll be able to hit your brakes on a big cam application and it won't kill itself from pulling a bunch of timing from a table you are not allowed to see. This will turn off Brake Torque Management on your P01 or "0411" PCM.

It will shut down the torque management but may also keep it in closed loop as well.