P0742

Circuit Description

The PCM controls the torque converter clutch (TCC) solenoid valve pulse
width modulation (PWM). The solenoid controls the hydraulic fluid for TCC apply and release. When the vehicle is accelerating, the PCM commands the TCC to be disengaged.

If the PCM detects a TCC slip from +50 to +135 RPM, when the TCC is commanded OFF, then DTC P0742 sets. DTC P0742 is a Type B DTC.

Conditions for Running the DTC

^ No MAF DTCs P0101, P0102, or P0103.
^ No TP DTCs P0121, P0122, or P0123.
^ No VSS DTCs P0502 or P0503.
^ No A/T Input (shaft) Speed Sensor (ISS) DTCs P0716 or P0717.
^ No TCC Stuck OFF DTC P0741.
^ No Transmission Fluid Pressure (TFP) manual valve position switch DTC P1810.
^ No TCC PWM solenoid valve DTC P1860.
^ The engine run time is greater than 5 seconds.
^ The engine is not in fuel cut off.
^ The TFP manual valve position switch indicates D4.
^ The transmission gear ratio indicates 2nd, 3rd or 4th gear.
^ The throttle angle is greater than 15.3 degrees.
^ The delivered torque is 160-220 N.m (118-162 lb ft).
^ The TCC is commanded OFF.

Conditions for Setting the DTC

The slip speed is +50 to +135 RPM for 5 seconds (slip speed equals engine speed minus transmission input shaft speed).

Action Taken When the DTC Sets

^ The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
^ SERVICE ENGINE SOON, SERVICE TRANSMISSION displays on the driver information center (DIC).
^ The PCM inhibits TCC engagement.
^ The PCM inhibits 4th gear if the transmission is in hot mode.
^ The PCM stores DTC P0742 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

Conditions for Clearing the MIL/DTC

^ The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
^ A scan tool clears the DTC from PCM history.
^ The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM.

Diagnostic Aids

Inspect the transmission fluid for sediment or debris.

Test Description

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

2. This step verified that the PCM commanded the TCC PWM solenoid valve OFF and the slip speed is +50 to +135 RPM for more than 5 seconds.
3. This step inspects and repairs the components that caused the DTC to set.