M99 - Automatic Transmission
DTC P0796 or P0797
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P0796
- Clutch Pressure Control (PC) Solenoid 3 - Stuck Off
DTC P0797
- Clutch Pressure Control (PC) Solenoid 3 - Stuck On
Circuit/System Description
The clutch pressure control (PC) solenoid 3 is part of the control solenoid (w/body and TCM) valve assembly and is not serviced separately. The transmission control module (TCM) supplies 12 volts to the clutch PC solenoid 3 on the high side driver 1 circuit. The TCM controls the PC solenoid 3 through the clutch PC solenoid 3 control circuit. The normally high clutch PC solenoid 3 controls fluid to hybrid low 1-2 and the 4th clutch assemblies when commanded ON and exhausts fluid when commanded OFF. The clutch PC solenoid 3 regulates the transmission fluid pressure to the hybrid low 1-2 and the 4th clutch assemblies.
Conditions for Running the DTC
No DTCs P0721, P0722 or P0723.
P0796
* The transmission OSS speed is greater than 60 RPM.
* Hybrid low 1-2 clutch is commanded ON.
P0797
* The transmission output shaft speed is greater than 200 RPM.
* Hybrid low 1-2 clutch is commanded OFF.
Conditions for Setting the DTC
P0796
The TCM detects an incorrect on-coming clutch gear ratio, or flare, when the XX clutch is commanded OFF for 0.5 seconds and the transmission XX speed is greater than 75 RPM from the anticipated XX speed.
P0797
The TCM detects an incorrect off-going clutch gear ratio, or tie-up, when the XX clutch is commanded ON for 0.5 seconds and the transmission input shaft speed is greater than 40 RPM from the anticipated input shaft speed.
Action Taken When the DTC Sets
* DTCs P0796 and P0797 are Type A DTCs.
* The TCM commands maximum line pressure.
* The TCM freezes transmission adaptive functions.
Conditions for Clearing the DTC
DTCs P0796 and P0797 are Type A DTCs.
Diagnostic Aids
When attempting to set transmission performance DTCs, observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views
Electrical Information Reference
* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs
* High Voltage Disabling
* High Voltage Enabling
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
* Scan Tool Output Controls (Scan Tool Output Controls)
* Scan Tool Data List (Scan Tool Data List)
* Scan Tool Data Definitions (Scan Tool Data Definitions)
Special Tools
* DT-47825 Control Solenoid Test Plate
* DT-47825-10 Jumper Harness
Circuit/System Verification
1. Perform the Transmission Fluid Check (Transmission Fluid Check) .
2. Turn ON the ignition, with the engine OFF.
Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records.
3. Record the DTC Freeze Frame and Failure Records.
4. Clear the DTC.
5. Operate the vehicle in DRIVE with the calculated throttle position greater than 15 percent to obtain 72 km/h (45 mph) and achieve 4th gear. Perform this maneuver 2 times.
• If the DTC resets, go to Circuit/System Testing.
Circuit/System Testing
1. Perform the Line Pressure Check (Line Pressure Check) .
• If the pressure is out of specification, correct this concern first.
2. Perform the Control Solenoid Valve and Transmission Control Module Assembly Cleaning (Control Solenoid Valve and TCM Assembly Solenoid Performance Test) and retest the DTC as outlined in the Circuit/System Verification steps.
• If the DTC resets, continue on with testing.
3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (Control Solenoid Valve and TCM Assembly Solenoid Performance Test) .
• If a concern is found, repair or replace the control solenoid (w/body and TCM) valve assembly.
4. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test (Control Solenoid Valve and TCM Assembly Solenoid Performance Test) .
• If the solenoid is found to be leaking or stuck closed, replace the control solenoid (w/body and TCM) valve assembly.
5. Inspect the control valve lower body assembly for sticking valves, damage, scored bores, or debris.
• If a concern if found in the valve body, repair or replace the valve body as necessary.
6. Inspect the hybrid low 1-2 clutch assembly for damage.
• If a concern is found in the hybrid low 1-2 clutch, repair or replace as necessary.
Component Testing
1. Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (Control Solenoid Valve and TCM Assembly Solenoid Performance Test) .
2. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test (Control Solenoid Valve and TCM Assembly Solenoid Performance Test) .
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
* Control valve body replacement. Refer to Control Valve Body Replacement (Control Valve Body Replacement) .
* Low and hybrid low 1-2 clutch assembly repair or replace. Refer to Hybrid Low 1-2 Clutch Overhaul .
* Control solenoid (w/body and TCM) valve assembly replacement. Refer to Control Module References for replacement, setup, and programming.