TCC Unlock Problems

[Rontune]

Hi. New to the Forum. I have been using a tune in a 99 vette with A4 and Yank SY3500 for sometime with no problems. Recently purchased EFILive and made a few re-flashes to change LTFTs and timing (no changes in the trans/TCC area) and now the TCC has begun intermittently unlocking in 3rd and 4th gear well above set disengage speeds. Happens under steady state, light load, or coasting conditions. P1870 is still set to not report, or set codes, and no codes are set when the TCC unlocks. I stumbled across an interesting thing…when PCM is shown on the DIC with no codes, if I hold down reset it relocks the TCC. Have been chasing this thing for a while with no luck. Frustrated. Any help or suggestions will be greatly appreciated. Can’t understand why it started unlocking after a few re-flashes, and don’t understand why “reset” relocks it when no codes are showing (no history codes ether).

[ChipsByAl]

If the PCM sees some misfires it will disable the TCC. You might not have the code set either. Monitor your misfires and see if the lockup comes off then.
AL

[Rontune]

If the PCM sees some misfires it will disable the TCC. You might not have the code set either. Monitor your misfires and see if the lockup comes off then.
AL

ChipsByAl. Hope I do this reply correctly, its the first for me. Thanks very much your input. The misfire codes are turned off, before and after the latest reflashes - and no codes are set when the unlocking occurs. Thats why it is strange that hioding down "reset" on the DIC when the PCM is displayed relocks the converter. The unlocking started immediately after a reflash - with no changes to trans/TCC parameters. Made changes to VE tables and timing, flashed, went for a drive, and the unlocking started. Reflashed the previous program back in, but unlocking continued.

[driver456]

I had the same problem but after a H/C install,My TC had a mind of its own.Somebody on this forum,Don't remember who,Told me to set {C5601} MISFIRE DETECTION MAX TEMP to 1 degree and it fixed my TC lockup problem.It was at 266 degree's.Now my TC works fine.I don't know if thats your problem ,But you can try it...................Paul

[Rontune]

ChipsByAl & driver456/Paul, thanks very much for the suggestions. At first I set them aside thinking it couldn’t be misfire, since I had shut off misfire by setting “Engine DTC Processing Enablers: P0300 Misfire – Not Reported” & “Engine DTC MIL Enablers: P0300 Misfire – No MIL” under Engine Diagnostics. Also, since I had not previously had misfire/unlock problems with it shut off in that manner. In any case, I took Paul up on his specific suggestion and set C5601 to 1 degree, and went for a drive. The torque converter “UNLOCKING PROBLEM" HAS BEEN SOLVED. Painful lesson, as much time and effort has been expended chasing this problem. I now know just shutting off the codes doesn’t do the trick. Thanks again for your help.

[ScarabEpic22]

I will try this tomorrow on my 02 TrailBlazer w/4L60E tranny. It started doing this same thing at random even before I started tuning right after I installed my Transgo HD-2 shift kit. Thanks for the help.

BTW, under which section is this located? Thanks!

[driver456]

ChipsByAl & driver456/Paul, thanks very much for the suggestions. At first I set them aside thinking it couldn’t be misfire, since I had shut off misfire by setting “Engine DTC Processing Enablers: P0300 Misfire – Not Reported” & “Engine DTC MIL Enablers: P0300 Misfire – No MIL” under Engine Diagnostics. Also, since I had not previously had misfire/unlock problems with it shut off in that manner. In any case, I took Paul up on his specific suggestion and set C5601 to 1 degree, and went for a drive. The torque converter “UNLOCKING PROBLEM" HAS BEEN SOLVED. Painful lesson, as much time and effort has been expended chasing this problem. I now know just shutting off the codes doesn’t do the trick. Thanks again for your help.

Ain't this forum cool.........................Paul

[joecar]

Ain't this forum cool.........................Paul

Good deal.