GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 SLS 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 6L50/6L80/6L90 🢒 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 Descriptors

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 clutch PC solenoid 3 flows fluid to the low and reverse, and the 4-5-6 clutch. The clutch PC solenoid 3 regulates the transmission fluid pressure to the low and reverse, and 4-5-6 clutch. The TCM calculates gear ratio based on data from the automatic transmission input speed sensor (ISS) and the output speed sensor (OSS). The TCM compares the known transmission gear ratio to a calculated gear ratio for each commanded gear.

Conditions for Running the DTC

P0796

    • For dynamic testing:
       - The Transmission Fluid Temperature (TFT) is greater than or equal to 0°C (32°F).
       - DTCs P0716, P0717, P0722, P0723, P1815, P1820, P1822, P1823, P1825, P1826 are not set.
       - The turbine speed is greater than or equal to 60 RPM, 4-5-6-R clutch is commanded ON
    • For 4th gear steady state testing:
       - Active the ignition voltage.
       - DTC P0716, P0717, P0722, P0723, P1915, P1825 are not set.
       - Active the high side driver.
       - The drive wheel speed is greater than or equal to 80 RPM.
       - The deviation of two wheel speeds at either side is less than or equal to 150 RPM.
       - The average deviation of the drive wheel and the driven wheel is less than 7 percent which could take up to 6 seconds.
       - The transmission is in 4th, 5th or 6th gear.
    •  For 5th gear steady state testing:
       - Active the ignition voltage.
       - DTCs P0716, P0717, P0722, P0723, P1915, P1825 are not set.
       - Active the high side driver.
       - The drive wheel speed is greater than or equal to 80 RPM.
       - The deviation of two wheel speeds at either side is less than or equal to 150 RPM.
       - The average deviation of the drive wheel and the driven wheel is less than 7 percent which could take up to 6 seconds.
       - The transmission is in 4th, 5th, or 6th gear.

P0797

    • Dynamic testing:
       - As PCS 3 or 4-5-6 reverse clutch commanded pressure is 0 kPa for a calibrated amount of time.
       - The obtained gear box slip is equal to or less than 40 RPM for the calibrated amount of time.
    • For steady state testing:
       - Active the ignition voltage.
       - DTCs P0716, P0717, P0722, P0723, P1915, P1825 are not set.
       - Active the high side driver.
       - With the brake pedal not depressing or gear torque varies exceeds 250 N·m (184 lb ft) in 0.35 second.
       - The drive wheel speed is greater than or equal to 80 RPM.
       - The deviation of two wheel speeds at either side is less than or equal to 150 RPM.
       - The average deviation of the drive wheel and the driven wheel is less than 7 percent which could take up to 6 seconds.
       - The change of the transmission output shaft speed is greater than 1,300 RPM per second.
       - Commanded gear equals 1st, 2nd, 4th or 6th and has obtained a gear ratio.

Conditions for Setting the DTC

P0796

Dynamic Test

    • High speed mode:
       - The transmission output shaft speed is greater than or equal to 60 RPM.
       - Commanded gear slip is equal to or greater than 100 RPM for 2.25 seconds.
    • Low Speed Mode:
       - The transmission output shaft speed is less than 60 RPM.
       - The turbine speed is greater than or equal to the calibrated value for 2.25 seconds.

For 4th gear steady state testing:

Fail Case 1 and Fail Case 2 must occur in sequential order.

Fail Case 1

The command gear equals third, transmission case slip speed is 100 RPM or greater for 5 seconds.

Fail Case 2

Commanded gear accelerates to 5th and 5th gear box slip is less than or equal to 35 RPM or gear box slip is equal to or less than 100 RPM and PC Sol. 2 commanded pressure is at maximum for 4 seconds.

The 5th gear steady state testing:

Fail Case 1 and Fail Case 2 must occur in sequential order.

Fail Case 1

The command gear equals third, transmission case slip speed is 100 RPM or greater for 5 seconds.

Fail Case 2

Commanded gear accelerates to 6th and 6th gear box slip is less than or equal to 35 RPM or gear box slip is equal to or less than 100 RPM and PC Sol. 4 commanded pressure is at maximum for 4 seconds.

P0797

Dynamic Test

Gear box slip is 40 RPM or less for 1.2 seconds.

Steady State Test:

Fail Case 1 and Fail Case 2 must occur in sequential order, and the transmission is not at 4th or 5th gear.

Fail Case 1

    • The transmission OSS speed drops less than or equal to a calibrated value.
    • The above conditions exist for up to 0.3 second.

Fail Case 2

The clutch is off-going and the difference of the gear speed is between 35-100 RPM for 4 seconds.

Action Taken When the DTC Sets
    • DTCs P0796 and P0797 are Type A DTCs.
    • The TCM commands maximum line pressure.
    • The TCM inhibits TCC.
    • The TCM freezes transmission adaptive functions.

Conditions for Clearing the DIC/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

Connector End View Reference

    •  Automatic Transmission Inline 16-Way Connector End View
    •  Automatic Transmission Internal Connector End Views
    •  Automatic Transmission Related Connector End Views

DTC Type Reference

    •  Diagnostic Trouble Code (DTC) Type Definitions
    •  Diagnostic Trouble Code (DTC) List/Type

Electrical Information Reference

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

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  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 .
  2. Turn ON the ignition, with the engine OFF.

    3. 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 5th gear. Perform this maneuver 2 times.
    6. ⇒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.
  2. Perform the Control Solenoid Valve and Transmission Control Module Assembly Cleaning and retest the DTC as outlined in the Circuit/System Verification steps.
    3. ⇒If the DTC resets, continue on with testing.
  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.
  4. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test .
    5. ⇒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 upper body assembly for sticking valves, damage, scored bores, or debris.
    6. ⇒If a concern if found in the valve body, repair or replace the valve body as necessary.
  6. Inspect the low and reverse/4-5-6 clutch assembly for damage.
    7. ⇒If a concern is found in the low and reverse/4-5-6 clutch assembly, repair or replace as necessary.

Component Testing

Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection .

PC Sol 3 Operation

Exercise

Normal Operation

Stuck OFF

Stuck ON

Steady State Gears 1st Braking 4, 5, 6

1st Braking, 4, 5, 6

1st Free Wheel, Neutral

1st Braking, 4, 5, 6

Steady State Gears, 1 Free Wheel 2, 3

1st Free Wheel, 2, 3

1st Free Wheel, 2, 3

1st Braking, 4, 5, 6

Garage Shift

Park/Neutral to Reverse/Drive

Neutral 1st Free Wheel

Forward Gear

Downshift from gears 4, 5, 6 to 1, 2, 3

1st Free Wheel, 2, 3

1st Free Wheel, 2, 3

1st Braking, 4, 5, 6

Upshift from gears 1, 2, 3 to 4, 5, 6

4, 5, 6

Neutral

4, 5, 6

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Control Valve Lower Body and Upper Body Replacement
    •  Low and Reverse Clutch Overhaul
    •  4-5-6 Clutch Overhaul
    •  Service Fast Learn Adapts
    •  Control Module References for TCM replacement, setup, and programming