DTC 79

Diagnostic Chart:

Wiring Diagram:

The Torque Converter Clutch is applied when Circuit 422 is grounded at the PCM.

INFORMATION FLAG PARAMETERS

Info. Flag 79 is set when the PCM has detected the following condition afier the TCC actuator circuit has been switched off electrically twice per ignition cycle.

^ Voltage from the TCC actuator to PCM terminal J3E14 (Circuit 422) is less than 2 - 2.5 volts.



TEST DESCRIPTION

Numbered steps below refer to numbered steps on chart.

1. This step verifies problem is still present.


2. If TCC fuse is OK, check for battery voltage on A/Trans relay side of fuse with engine running or PCM in diagnostic mode.


3. This step checks for a ground in Circuit 1529. A ground in Circuit 1529 will cause the TCC actuator fuse to fail and set Info. Flag 79.

4. An open in Circuit 1529 will cause Info. Flag 79 to set. Check Circuit 1529 for opens.

5. This step indicates harness failure or actuator connector plate failure.

6. This step will indicate an actuator or connector plate failure.


7. An open or a ground in Circuit 422 will set Info. Flag 79. This step checks Circuit 422 for opens or grounds.

DIAGNOSTIC AIDS

When attempting to diagnose an intermittent problem use the Scan tool* to review supplemental diagnostic information. The supplemental data can be used to duplicate a problem.

* Select MALF History from Scan tool TCM menu.


Check the tightness of the female terminal grip with a spare male terminal.

When the PCM detects a fault in the circuit (open, ground, short) the PCM will open the circuit internally to protect the circuit.