P1860

Diagnostic Chart:

Diagnostic Chart (cont'd):

Wiring Diagram:

CIRCUIT DESCRIPTION

The TCC Pulse Width Modulation (PWM) Solenoid Valve controls the fluid acting on the converter clutch valve, which then controls the application and release of the TCC. The solenoid attaches to the control valve body within the transmission. Circuit 439 supplies ignition voltage directly to the solenoid. The PCM 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 Solenoid Valve provides a smooth engagement of the torque converter clutch by operating during a duty cycle percent of ON time. When the PCM detects a continuous open or a short to ground in the TCC PWM circuit or the TCC PWM Solenoid Valve, then DTC P1860 sets. DTC P1860 is a type A DTC.

CONDITIONS FOR SETTING THE DTC

- No system voltage DTC PP0560

- The ignition is ON.

- The PCM commands first gear.

- The PCM commands the solenoid to 0% and the voltage remains high (B+).

- All conditions met for 5 seconds

ACTION TAKEN WHEN THE DTC SETS

- The PCM inhibits TCC engagement

- The PCM inhibits 4th gear if in hot mode

- The PCM freezes shift adapts from being updated.

- The PCM illuminates the Malfunction Indicator Lamp (MIL).

CONDITIONS FOR CLEARING THE MIL/DTC

- The PCM turns OFF the MIL after three consecutive ignition cycles without a failure reported.

- A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.

- The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.

DIAGNOSTIC AIDS

- Inspect the wiring for any poor electrical connections at the PCM. Inspect the wiring 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 an 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 chart.

4. Step 4 verifies that the solenoid receives current.

6. Step 6 verifies the ability of the PCM and the wiring to control the ground circuit.

8. Step 8 measures the resistance of the TCC PWM Sol. Valve and the Automatic Transmission wiring harness.