P079B
DTC P079B
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P079B
- Transmission Clutch 2 Slip Detected
Circuit/System Description
The transmission control module monitors hybrid direct, 2-3-4 clutch slip speed when the hybrid direct, 2-3-4 clutch is applied. The hybrid direct, 2-3-4 clutch is displayed as Clutch 2 on the scan tool. The transmission control module is part of the control solenoid valve assembly and is not serviced separately.
Conditions for Running the DTC
* Hybrid direct, 2-3-4 clutch is applied.
* The clutch pressure control solenoid 2 commanded pressure is 1800 kPa (261 psi) for 3 seconds.
Conditions for Setting the DTC
The transmission control module detects the hybrid direct, 2-3-4 clutch slip speed is greater than 200 RPM for 3 seconds.
Action Taken When the DTC Sets
* P079B is a Type B DTC.
* The transmission control module inhibits gear 2, gear 3, gear 4 and Mode 2.
Conditions for Clearing the DTC
P079B is a Type B DTC.
Diagnostic Aids
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.
Reference Information
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information.
Special Tools
DT-47825 - Control Solenoid Test Plate
For equivalent regional tools, refer to Special Tools Tools and Equipment.
Circuit/System Verification
1. Verify that DTCs P0721, P0722, P0723, P0966, P0967, P0969, P0970, P0971, P0973, P0974, P0976, P0977, P2720, P2721, P2728, P2729, or P2730 is not set.
• If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
2. Perform the Transmission Fluid Level and Condition Check Testing and Inspection to verify correct fluid level and condition.
3. Perform the Line Pressure Check Line Pressure Check to verify correct oil pressure.
4. Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection Control Solenoid Valve and Transmission Control Module Assembly Inspection to verify Q8 control solenoid valve assembly condition.
5. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test to verify Q8 control solenoid valve assembly function.
6. Listed in the chart below are conditions for each component that could set DTC P079B. Carefully inspect each component for that condition. Repair or replace as necessary.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Control Valve Assembly Disassemble Control Valve Assembly Disassemble for Valve Body Inspection procedures.
* Control Valve Upper Body Replacement Service and Repair for Control Valve Body replacement.
* Hybrid Direct, 2-3-4 Clutch Housing Overhaul Hybrid Direct, 2-3-4 Clutch Housing Overhaul for Hybrid Direct, 2-3-4 Clutch replacement.
* Control Module References Control Module References for Control Solenoid Valve Assembly replacement, programming and setup.
* Perform the Reset Transmission Adapts Reset Procedure following all transmission related repairs.