2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 1840
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.
瀚慖f any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code
Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle).
2. Perform the Transmission Fluid Level and Condition Check (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Testing
and Inspection/Symptom Related Diagnostic Procedures/2ML70 - Automatic Transmission/Transmission Fluid Level and Condition Check)
to verify correct fluid level.
3. Perform the Line Pressure Check (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Testing and Inspection/Component
Tests and General Diagnostics/2ML70 - Automatic Transmission/Line Pressure Check) to verify correct oil pressure.
4. Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (See: Transmission and Drivetrain/Automatic
Transmission/Transaxle/Testing and Inspection/Component Tests and General Diagnostics/2ML70 - Automatic Transmission/Control
Solenoid Valve and Transmission Control Module Assembly Inspection) to verify control solenoid valve assembly condition.
5. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test (See: Transmission and
Drivetrain/Automatic Transmission/Transaxle/Testing and Inspection/Component Tests and General Diagnostics/2ML70 - Automatic
Transmission/Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test) to verify control solenoid
valve assembly function.
6. Inspect the trans fluid pump ball check valve for possible sticking or damage.
瀚慖f you found a concern with this check ball, repair the concern.
7. Inspect the hybrid low, 1-2 clutch boost valve assembly and the hybrid low, 1-2 clutch regulator valve assembly for sticking or damage.
瀚慖f 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.
8. Inspect the 4th clutch assembly for a slipping or damaged condition.
瀚慖f you found a 4th clutch assembly concern, repair or replace the low and reverse clutch assembly as necessary.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Control Valve Assembly Disassemble (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Service and
Repair/Overhaul/2ML70 - Automatic Transmission/54. Control Valve Assembly Disassemble) for valve body inspection procedures.
* Control Valve Upper Body Replacement (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Valve Body/Service and
Repair/2ML70 - Automatic Transmission) for control valve body replacement.
* 4th Clutch Piston Removal (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Service and Repair/Overhaul/2ML70 -
Automatic Transmission/10. 4th Clutch Piston Removal) for 4th clutch inspection.
* 4th Clutch Piston Installation (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Service and Repair/Overhaul/2ML70 -
Automatic Transmission/35. 4th Clutch Piston Installation) for 4th clutch assembly replacement.
* Control Module References (See: Testing and Inspection/Programming and Relearning) for control solenoid valve assembly replacement,
setup, and programming.
P079D
DTC P079D
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P079D
- Transmission Clutch 4 Slip Detected
Circuit/System Description
The transmission control module monitors the 1-3 clutch slip speed when the 1-3 clutch is applied. The 1-3 clutch is displayed as Clutch 4 on the
