I have a 2001 4l60e that I rebuilt a couple years ago and has around 20K miles on it. It has a stock lockup converter with a Transgo shift kit. It has worked fine until a month a go it went in to the limp mode and gave the code that 1-2 solenoid failed. So I replaced both shift solenoids. Put it back together and it shifts fine but has no lockup on the torque converter. So I replaced the harness and TCC solenoid. Still shifts fine but no lockup on the torque converter. So with trying to diagnose this thing what requirements dose the computer need before it will send a signal to the TCC to lock the converter. I do have a OTC Genesis scanner, I can see more things than the cheaper scanners. Any help would be great.

 

I guess I should say that I know vehicle speed, trans temp, engine temp and throttle position are the normal things that need to be met for the PCM to lock the converter. What I'm looking for is any problems the computer may see that doesn't set a code but would cause the PCM to not lock the converter. Why I ask is that I had a Blazer that had a misfire that was not bad enough to set a code but would prevent the PCM from locking the converter.

 

Scan the PID for the TCC solenoid, if the solenoid is commanded on and the converter does not lock the problem is not in the PCM/TCM.