With 3 Speed Automatic

P0742 WITH 3 SPEED AUTOMATIC

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The Torque Converter Clutch Solenoid Valve (TCC Sol. Valve) receives power from the fuse panel, on circuit 439. The normally-open 3rd clutch pressure switch interrupts the ground path from the TCC Sol. Valve. The PCM activates the TCC Sol. Valve by grounding the circuit through an internal switch in the PCM. Although the PCM commands the TCC Sol. Valve ON, the converter clutch does not apply until the 3rd clutch oil (3rd clutch engaged) closes the pressure switch, completing the circuit. Activating the TCC Sol. Valve blocks exhaust fluid. This moves the converter clutch control valve to the applied position, and provides fluid pressure to engage the torque converter clutch.

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

CONDITIONS FOR SETTING THE DTC

^ No Throttle Position (TP) sensor DTC P0122 or P0123

^ No Vehicle Speed Sensor Assembly DTC P0502

^ The PCM has commanded the TCC OFF.

^ The speed ratio is 0.98-1.406.

^ The throttle angle is 18-60%.

^ The slip speed is -20 to +20 RPM for 5 seconds.

^ The MAP is 20.3-36.56 kPa.

^ The vehicle speed is 56-105 km/h (35-65 mph).

^ The engine speed is 1500-3300 RPM.

^ All of the above conditions are met three consecutive times.

ACTION TAKEN WHEN THE DTC SETS

The PCM illuminates the Malfunction Indicator Lamp (MIL) after two ignition cycles with a failure reported.

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.

DIAGNOSTIC AIDS

If the vehicle stalls repeatedly, the TCC is mechanically stuck ON.

TEST DESCRIPTION

The numbers below refer to the Step numbers on the diagnostic table.

2. This Step determines whether the stuck ON condition is due to an electrical failure, or a mechanical failure.

3. This Step tests for a short to ground on circuit 422 between the transmission wiring harness and the PCM.