TCC Apply issues (PCM related)

[OneSlowGTP]

I have a 99 GTP with tons of mods.

My TCC Apply seems to have a mind of it's own.

Some days it locks up just like the tables say it should

Other days it never locks up

I did a scan of TCC status / slip rpm / duty cycle.

When TPS is at 0% the TCC status displays as: OFF

At 1% or more throttle the status changes from OFF to a few --- marks.

Once conditions are met for lockup, it *sometimes* displays "APPLY" and the silp factor begins reducing to ~20rpm and then the status changes to "LOCKED"

Other times, I can meet all the requirements of lockup (drive ~55 at 3% TPS) yet the lockup will not always occur... When it works, it works fine, but when it doesn't, it continues to display --- as if it is waiting for all operating conditions to be met.

There MUST be additional fields that not been discovered/unlocked by HPTUNERS? Anyone else experience this problem?

How sensitive is lockup? will it not occur if it thinks your air/fuel is off? Calculated load too high? ECT too low? Maybe it thinks it's more efficient to "not" lockup so it doesn't? aaarghhhhh

[OneSlowGTP]

I see quite a few other people are having similar issues? Has any fix been discovered for this yet?

[Bill@HPTuners]

personally ive never had issue other then when my tranny temp is low it wont lock...other then that Its always locked when its supposed to. It does unlock when i go to 0% tps though

[coachcrow56]

I am having the same problem. I have never had tranny issues until I installed an S1X cam last weekend. Now on two occasions my tranny has refused to shift into 4th--takes about a mile before it decides to finally shift---and this is under light throttle conditions (driving like grandpa).

[mbarber]

Sorry to hijack the thread but I too have TCC issues. I installed a new ZZP tranny with 3.29 gears and now my converter jumps back and forth between lock and unlock then it locks and sets the P0742 TCC stuck on code and shifts hard as hell. I contacted ZZP and he says "you have the gear ratio stuff setup improperly in the PCM and it's going into backup mode." I did set my drive sprocket to 1.00 and the speedo reads ok is there anything else I need to do?