Good Morning all,

I am hoping that there is someone on here that can help figure this one out. About 1 year ago, I had an Engine installed in this thing. It drove fine for about 6 months.

Then Check engine light comes on with a PO1870 TCC Slippage code and PO 785 (3-2 solenoid electrical fault).

I found some mechanical causes for the 1870 after doing some research- Replaced TCC solenoid with and updated one, replaced all solenoids and transmission internal harness while I was there.

The truck has not made it out of the driveway. The codes will clear and within seconds of being turned on. The. 785 code returns and the transmission pressure gets maxed out as well as the trans being stuck in 3rd.

Here is what else has been done or checked.

1) checked for proper voltage to the PCM terminals for Batter Pos. and Ignition Pos. - Passed tests
2) Isolated those same pcm circuits and performed a load test and volt drop test. - both passed with less .1v dropped and a 4amp load test passed
3) same tests performed on 2 available pct grounds- .1v dropped and a 4 amp load test passed
4) checked terminal E ( solenoid power for proper sully voltage- Passed (close to source voltage present)
5) Isolated terminal E and terminal S from the system and performed volt drop and load tests- both passed

A co-worker mentioned running an overlay for circuit 687/ terminal S at the transmission pigtail. I did that and still have the failure.


any assistance would be appreciated.

Thanks,


Dennis_P

 

Welcome to the forum.