P0742

Diagnostic Chart:

Wiring Diagram:

Circuit Description
The PCM energizes the Torque Converter Clutch Solenoid Valve (TCC Sol. Valve) by creating a ground path on circuit 422. When grounded (energized) by the PCM, the TCC Sol. Valve stops converter signal oil from exhausting. This causes converter signal oil pressure to increase and move the TCC valve. The TCC Sol. Valve de-energizes when the PCM no longer provides a ground path. When the TCC Sol. Valve de-energizes, the valve exhausts fluid and releases the TCC.

When the PCM detects low torque converter slip when the PCM commands the TCC OFF, then DTC P0742 sets. DTC P0742 is a type B DTC.

Conditions for Setting the DTC
DTC P0742 sets if the following conditions occur once per TCC cycle, two consecutive times:

^ No MAP DTCs P0106, P0107 or P0108.
^ No Throttle Position (TP) DTCs P0122 or P0123.
^ No Vehicle Speed Sensor Assembly (VSS Assy.) DTCs P0502 or P0503.
^ No TCC Sol. Valve DTC P0740.
^ No TFP Val. Position Sw. DTC P1810.
^ No TCC Pulse Width Modulation (PWM) Sol. Valve DTC P1860.
^ The TP angle is 15-60%.
^ The engine speed is greater than 450 RPM for 8 seconds.
^ Not in fuel cutoff.
^ The engine speed is 1000-3000 RPM.
^ The engine torque is 50-400 lbs ft.
^ The engine vacuum is 0-105 kPa.
^ The speed ratio is 0.65-1.25 (the speed ratio is engine speed divided by output speed).
^ The vehicle speed is 32-104 km/h (20-65 mph).
^ The commanded gear is not 1st. The gear range is D4.
^ No gear range change within 6 seconds.
^ The PCM commands the TCC OFF.
^ The TCC slip speed is -20 to +20 RPM.
^ All conditions met for 5 seconds.

Action Taken When the DTC Sets

^ 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

^ The TCC fluid will mechanically apply the TCC, possibly causing an engine stall under the following conditions:

- The TCC is mechanically stuck ON
- The parking brake is applied
- Any gear range is selected
^ A stuck TP sensor sets DTC P0742.

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

3. This step inspects the mechanical state of the TCC. When the PCM commands the TCC Sol. Valve OFF, the slip speed should increase.