Eric LeBlanc

Hey everyone. I installed a 5.3 with a 4l80e into my 79 Camaro. I installed a turbo setup and a harness from PSI. It has had a partial tune so that it runs and drives. I am getting a P1860 code which has to deal with the torque converter lock up. I removed the transmission and verified the Oring on the input shaft. I have checked the harness to the transmission and it has continuity on the brown wire(pin2). I have verified 12v from the lock up/brake switch to the computer and it is there until the brakes are applied. I also spliced a wire that I could ground while driving to enable the lockup and it works without a doubt. So, I am not sure where to go from here. The tuner says that there is nothing wrong with the tune and won't tune it until I figure out the issue because he needs it to lockup for the tune because it is speed density.

clinebarger

DTC 1860 is for a TCC PWM electrical fault.

All conditions for running the DTC are met, and either of the following conditions occur.

•The PCM commands the TCC PWM solenoid valve to OFF, 0 percent, and the voltage input remains low, zero volts.
•The PCM commands the TCC PWM solenoid valve to ON, 100 percent, and the voltage input remains high, B+.

Unplug C1 & C2 from the PCM, Turn the key on, Probe pin 2 (C2) with a test light or volt meter, Should be real close to battery voltage.
If no voltage is present? Let me know.

If Voltage is present, Use a 5amp fused jumper & Ground pin 2, Should hear an audible click from the TCC PWM solenoid.

Eric LeBlanc

Just to clarify, I took the line that goes to the transmission (pin s on the connector) and attached a wire to it so I can ground it while driving. When doing this, the transmission does lock up.
I unplugged both connectors from the computer and verified pin 2 has voltage. I know the solenoid works from previous testing in and out of the car.
Still at a loss on what to do to clear it or why it is there

clinebarger

If your sure the wire/circuit/Terminal/PCM pin is good. The Driver or Circuit monitor in the PCM could be faulty requiring a new/different PCM to fix your issue.

PCM driver failures are few & far between on stock vehicles, But seems to be more common on "Swap" vehicles with "Tuned" PCM's.

Do you have a Scanner/Software capable to command the PWM solenoid "On" via the PCM?

Eric LeBlanc

i am pretty confident that the wire from the trans is in working order. I do not have a scanner to be able to do that. It has only had a basic tune and that is one of the fault codes besides electric fans and MAF which show up. When driving the car it shifts fine but will not go into 4th gear until around 55 MPH. Once it is in gear I can go slower than that and it will stay in 4th. Just never locks up