4T65-E Automatic Transaxle

DTC P1860















Circuit Description with 4T65-E Automatic Transaxle
Ignition voltage is provided to the torque converter clutch pulse width modulation (TCC PWM) solenoid valve. The PCM controls the solenoid with a negative duty cycle in order to control application and release of the TCC. When the solenoid is commanded OFF, the PCM senses high voltage. When the solenoid is commanded ON, the PCM senses low voltage.
DTC P1860 sets if the PCM detects a voltage that is outside of the calibration limits. DTC P1860 is a type B DTC.

Conditions for Running the DTC
^ The system voltage is 9 - 18 volts.
^ The engine speed is greater than 500 RPM for 5 seconds and not in fuel shut off.

Conditions for Setting the DTC
DTC P1860 sets when one of the following conditions exists for at least 5 seconds:
^ The PCM commands the solenoid to greater than 90% duty cycle and the voltage feedback remains high (B+).
^ The PCM commands the solenoid to less than 10% duty cycle and the voltage feedback remains low (0 volts).

Action Taken When the DTC Sets
^ The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the conditions for setting the DTC are met.
^ The PCM inhibits TCC.
^ The PCM inhibits 4th gear if the transmission is in Hot Mode.
^ The PCM freezes shift adapts.
^ The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
^ The PCM stores DTC P1860 in PCM history during the second consecutive trip in which the conditions for setting the DTC are met.

Conditions for Clearing the MIL/DTC
^ The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
^ A scan tool can clear the MIL/DTC.
^ The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
^ The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. A short to ground in the power feed circuit to the solenoid ahead of the splice would open the fuse and set DTCs for other solenoids on the same circuit. An open in the same circuit would not open the fuse but would set the other DTCs.