P1860

Diagnostic Chart:

Wiring Diagram:

Circuit Description
The Torque Converter Clutch Pulse Width Modulation Solenoid Valve (TCC PWM Sol. Valve) controls the fluid acting on the converter clutch valve. The converter clutch valve controls the TCC application and release. The solenoid attaches to the control valve body within the transmission. The solenoid receives ignition voltage through circuit 1020. The VCM controls the solenoid by providing a ground path on circuit 418. Current flows through the solenoid coil according to the duty cycle (percentage of ON and OFF time). The TCC PWM Sol. Valve provides a smooth engagement of the TCC by operating during a duty cycle percent of ON time. When the VCM detects a continuous open or short to ground in the TCC PWM Sol. Valve circuit or the TCC PWM Sol. Valve, then DTC P1860 sets. DTC P1860 is a type A DTC.

Conditions for Setting the DTC

^ The system voltage is 10-19 volts.
^ The engine speed is greater than 450 RPM for 8 seconds.
^ TCC duty cycle is 10-90%.
^ Not in fuel cutoff.
^ The VCM commands first gear.
^ All of the above conditions are met for 5 seconds and either of the following fail conditions occurs for 5 seconds:

- The VCM commands the solenoid ON (90%) and the voltage remains high (B+).
- The VCM commands the solenoid OFF (0%) and the voltage remains low (0 volt).

Action Taken When the DTC Sets

^ The VCM inhibits TCC engagement.
^ The VCM inhibits 4th gear if the transmission is in hot mode.
^ The VCM freezes shift adapts from being updated.
^ The VCM illuminates the Malfunction Indicator Lamp (MIL).

Conditions for Clearing the MIL/DTC

^ The VCM turns OFF the MIL after three consecutive ignition cycles without a failure reported.
^ A scan tool can clear the DTC from the VCM history. The VCM clears the DTC from the VCM history if the vehicle completes 40 warm-up cycles without a failure reported.
^ The VCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the VCM.

Diagnostic Aids

^ Inspect the wiring for poor electrical connections at the VCM. Inspect the wiring for poor electrical connections at the transmission 20-way connector. Look for the following conditions:

- A bent terminal.
- A backed out terminal.
- A damaged terminal.
- Poor terminal tension.
- A chafed wire.
- A broken wire inside the insulation.

^ When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.

Test Description
The numbers below refer to the step numbers on the diagnostic table.

4. This step tests for voltage to the solenoid.
6. This step tests the ability of the VCM and wiring to control the ground circuit.
8. This step tests the resistance of the TCC PWM Sol. Valve and the Automatic Transmission Wiring Harness Assembly.