The transmission control module (TCM) monitors the Clutch Slip Speed for each Hybrid Trans. Mode Commanded state. This DTC detects clutch slip when the 4th clutch is commanded ON, indicating a slipping clutch condition.

The clutch PC solenoid 3 commanded pressure is 1800 kpa (261 psi) for 3 seconds.

The TCM detects the clutch 4 slip speed is greater than 200 RPM for greater than 3 seconds.

P079C is a Type B DTC.

When attempting to set transmission performance DTCs, observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions. Ensure the transmission fluid level is correct and there are no leaks. If there are any other transmission DTCs set, diagnose those first.

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

1. Verify that DTCs P0721, P0722, P0723, P0966, P0967, P0969, P0970, P0971, P0973, P0974, P0976, P0977, P2720, P2721, P2728, P2729, or P2730 are not set.

⇒	If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.

2. Clear the DTC.
3. Operate the vehicle from 3rd through 4th gear while observing the Clutch 4 Slip Speed parameter. Stop the vehicle and turn the ignition OFF for 30 seconds. Perform this action 2 times. The Clutch 4 Slip Speed parameter should display 0 RPM when the Clutch 4 Status parameter displays Applied.

⇒	If any other transmission DTCs set, diagnose those first.

⇒	If DTC P079C resets, go to Component Testing.

1. Perform the Line Pressure Check.
2. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test.

⇒	If a concern is found, replace the control solenoid (w/body and TCM) valve assembly.

3. Inspect the trans fluid pump ball check valve for possible sticking or damage.

⇒	If you found a concern with this check ball, repair the concern.

4. Inspect the hybrid low, 1-2 clutch boost valve assembly and the hybrid low, 1-2 clutch regulator valve assembly for sticking or damage.

⇒	If you found a concern with the hybrid low, 1-2 clutch boost valve assembly or the hybrid low, 1-2 clutch regulator valve assembly, repair or replace the valve or valve body.

5. Inspect the 4th clutch assembly for a slipping or damaged condition.

⇒	If you found a 4th clutch assembly concern, repair or replace the low and reverse clutch assembly as necessary.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.