GM Service Manual Online
For 1990-2009 cars only

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 Descriptors

DTC P0796: Pressure Control (PC) Solenoid 3 - Stuck Off

DTC P0797: 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

P0796 or P0797

    • The engine run time is greater than 1 second.
    • SS valve 1 is not in a transition state.
    • The transmission line pressure is greater than 370 kpa (54 psi) and not fluctuating by greater than 30 kpa (4 psi).
    • Propulsion is active.

P0796

The clutch PC solenoid 3 commanded pressure is greater than 1800 kpa (261 psi) for 4.5 seconds.

P0797

The clutch PC solenoid 3 commanded pressure is less than 5 kpa (1 psi) for 4.5 seconds.

Conditions for Setting the DTC

P0796 - Fail Case 1

The clutch PC solenoid 3 commanded pressure is 1800 kpa (261 psi) and the TFP switch 2 state is Low for 30 seconds.

P0766 - Fail Case 2

The clutch PC solenoid 3 commanded pressure is 1800 kpa (261 psi) and the TFP switch 2 state is Low for 0.5 seconds greater than 5 times during a key cycle.

P0797 - Fail Case 1

The clutch PC solenoid 3 commanded pressure is 5 kpa (1 psi) and the TFP switch 2 state is High for 36 seconds.

P0797 - Fail Case 2

The clutch PC solenoid 3 commanded pressure is 5 kpa (1 psi) and the TFP switch 2 state is High for 1.25 seconds greater than 5 times during a key cycle.

Action Taken When the DTC Sets

    • P0796 and P0797 are Type B DTCs.
    • The TCM commands maximum line pressure.
    • The TCM freezes transmission adaptive functions.

Conditions for Clearing the DTC

P0796 and P0797 are Type B 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

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information.

Special Tools

DT-47825 Control Solenoid Test Plate Kit

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 are not set.
  2. If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  3. Perform the Transmission Fluid Check.
  4. Turn ON the ignition, with the engine OFF.
  5. Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records.

  6. Record the DTC Freeze Frame and Failure Records.
  7. Clear the DTC.
  8. Operate the vehicle in DRIVE to obtain 72 km/h (45 mph) and achieve 4th gear, stop the vehicle, turn the ignition Off for at least 30 seconds. Perform this 2 times.
  9. If the DTC resets, go to Circuit/System Testing.

Circuit/System Testing

  1. Perform the Line Pressure Check.
  2. If the pressure is out of specification, correct this concern first.
  3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection.
  4. If a concern is found, repair or replace the control solenoid (w/body and TCM) valve assembly.
  5. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test.
  6. If the solenoid is found to be leaking or stuck closed, replace the control solenoid (w/body and TCM) valve assembly.
  7. Inspect the control valve lower body assembly for sticking valves, damage, scored bores, or debris.
  8. If a concern if found in the valve body, repair or replace the valve body as necessary.
  9. Inspect the hybrid low, 1-2 clutch assembly for damage.
  10. 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.
  2. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Control Solenoid Valve and Transmission Control Module Assembly Replacement.
    •  Hybrid Low, 1-2 Clutch Piston Removal and Hybrid Low, 1-2 Clutch Piston Installation for low and hybrid low, 1-2 clutch assembly repair or replacement.
    •  Control Module References for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming.