Got a small oddity here. Tuner doesn't know why it is happening.

When I plug in my scan tool to read the data (generic engine operational data, nothing fancy) while driving, the torque converter begins to cycle off-on...off-on...off-on...etc.

The TCC will stay engaged as long as the engine is under practically no load (like going downhill) but then when climbing a hill the cycle begins again. The TCC is supposed to be staying locked at the given throttle angle and load values, but what could a scan tool (read-only, I would add) be doing to freak out the TCC?

I have only noticed this issue since I swapped in the 80E and used Frost's 2-relay conversion harness.

 

I had TCC issues when I swapped in my 4l80 but it was slightly different as mine would not be commanded on over 60-65mph. I had a p0300 misfire code that i found out prohibited the TCC function.
does the scan show it bieng commanded on off on off? can you override the PCM and command it on?

 

i have the segment swap BTW

 

Log total misfires and see if that is the cause.

 

Misfire detection is disabled in the PCM and the scan tool is not capable of reading that data in realtime.

 

I have heard of a couple oddities associated with the relay method, this is a new one.