No TCC lockup... help!

[YGETV8]

This is on my Mazda hybrid, so it's a unique situation. I didn't have TCC when I bought it, but I noticed the ECM speed read about half of actual, so figured that was the issue. Had my TurboTweak chip burned to account for that, but still nothing (now seeing the TCC command at the right speeds, though). So, thought maybe it was the old trans... till I installed my new one and still nothing! It's *probably* a wiring issue, but I'm not sure where to look? I mean, it's got the Buick wiring harness and ECM and there is the four wire connector going into the trans. Sounds pretty straightforward to me! Can I jumper one if those four wires to 12V or ground for testing purposes?

TIA, Jay

[TurboDave]

The Buick TCC wiring also included a provision for running through a switch on the brake pedal, so even the smallest application of brake pedal released the TCC.

[YGETV8]

True, but if that was the culprit I don't think I'd see the ECM commanding TCC. Sound correct?

I should have mentioned that I also have a Casper's VSS which I heard one person say they had bad luck with, but I still think if it was wiring TO the ECM or VSS related, I'd not see a TCC command on Direct Scan?

Thanks, Jay

[getchasum]

Jay, Last year I had a problem with the tcc, tried every thing from replacing the seliniod, chip, brarke switch, chased down the wires looking for a bad ground, turn out the ecm was giving trouble & a replacment cured my problem.

[YGETV8]

Good to know. Thanks!

[Scott King]

Originally Posted by YGETV8

True, but if that was the culprit I don't think I'd see the ECM commanding TCC. Sound correct?

Thanks, Jay

The Ecm supplies ground to the tcc solenoid. The brake switch opens the positive circuit, so yes the ecm will still command tcc when the brake pedal is pushed.

[YGETV8]

Ah! I bet that's the culprit then. Guess I'll try to hunt down the wires and adapt it to the Mazda brake switch. Seeing how me and wiring seem to HATE each other, should be fun!