P1860

Circuit Description
Ignition voltage is provided to the torque converter clutch pulse width modulation (TCC PWM) solenoid valve. The PCM controls the ON and OFF time of the solenoid by providing a ground through the output driver module (ODM) B. The PCM uses a PWM 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, when PCM senses low voltage.
DTC P1860 sets anytime the received voltage 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 4.3 seconds:
^ The PCM commands the solenoid to greater than 90% duty cycle and the voltage remains high (B+) or:
^ The PCM commands the solenoid to less than 10% duty cycle and the voltage 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 stores DTC P1860 in PCM history.

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 clears the DTC from the PCM history.
^ The PCM clears the DTC from the PCM history if the vehicle completes 40 consecutive warm-up cycles without an emission related diagnostic fault occurring.
^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM.

Diagnostic Aids
^ Inspect the wiring at the PCM, the transmission 20-way connector, the TCC PWM solenoid valve connector and all Other circuit connecting points for the following conditions:
- A backed out terminal
- A damaged terminal
- Reduced terminal tension
- A chafed wire
- A broken wire inside the insulation
- Moisture intrusion
- Corrosion
^ When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.
^ Ensure that the transmission fluid is at the proper level.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
6. This step isolates the engine harness from the transmission harness. Use a test lamp in order to verify the circuitry.
8. This step verifies that circuit 418 is not open or shorted to power.
10. This step verifies that the TCC PWM solenoid is not shorted across its windings or increased its resistance.
17. Because of the harsh conditions inside the transmission, repairing the automatic transmission (A/T) wiring harness is not acceptable. You must replace the A/T wiring harness assembly.