P0742

Diagnostic Chart:

Wiring Diagram:

Circuit Description
The PCM energizes the Torque Converter Clutch (TCC) Pulse Width Modulated (PWM) Sol. Valve by creating a ground path on circuit 418. When grounded by the PCM, the TCC PWM Sol. Valve stops the converter signal oil from exhausting, which causes the convener signal oil pressure to increase and move the TCC valve. The TCC PWM Sol. Valve de-energizes when the PCM no longer provides a ground path. When the TCC PWM Sol. Valve de-energizes, it exhausts fluid and releases the TCC. When the PCM detects low torque converter slip when the TCC is commanded OFF, then DTC P0742 sets. DTC P0742 is a type B DTC.

Conditions for Setting the DTC
The following conditions occur once per TCC cycle two consecutive times:

^ No Accelerator Pedal Position (APP) Sensor DTCs P0121, P0122, P0220, P0221, P0222, P0223, P0225, P0226, P0227, or P0228.
^ No engine speed DTC P0219.
^ No Input Speed (ISS) Sensor DTCs P0716 or P0717.
^ No TCC PWM Sol. Valve DTCs P0741 or P1860.
^ No Transmission Fluid Pressure (TFP) Valve Position Sw. DTC P1810.
^ No MAP Sensor DTCs P0106, P0107, or P0108.
^ The engine speed is less than 3650 RPM.
^ The engine must run for greater than 5 seconds.
^ The engine torque must be 10-565 Nm (80-450 lb ft).
^ The gear range is D4.
^ The commanded gear must be 2nd, 3rd, or 4th.
^ The APP Sensor must be greater than 10%.
^ The TCC slip speed must be -15 to +20 RPM for at least 5 seconds.
^ All conditions met for 3 occurrences.

Action Taken When the DTC Sets

^ The PCM commands maximum line pressure.
^ The PCM freezes shift adapts.
^ The PCM illuminates the Malfunction Indicator Lamp (MIL).

Conditions for Clearing the MIL/DTC

1. The PCM turns OFF the MIL after three consecutive ignition cycles without a failure reported.
2. 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.
3. 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

^ If the TCC is mechanically stuck On with the parking brake applied and any gear range selected, the TCC fluid mechanically applies the TCC. TCC fluid mechanically applying the TCC can cause an engine stall.
^ A stuck or skewed Throttle Position (TP) Sensor may set DTC P0742.
^ First diagnose and clear any engine DTCs or APP Sensor codes that are present. Then inspect for any transmission DTCs that may have reset.

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

3. This step tests the mechanical state of the TCC. When the PCM commands the TCC solenoid 0FF, the slip speed should increase.