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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 SLS 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 DTC P0776 or P0777

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 P0776:  Clutch Pressure Control (PC) Solenoid 2 - Stuck Off

DTC P0777:  Clutch Pressure Control (PC) Solenoid 2 - Stuck On

Circuit/System Description

The clutch pressure control (PC) solenoid 2 is part of the control solenoid (w/body and TCM) valve assembly and is not serviced separately. The clutch PC solenoid 2 flows fluid to the 3-5-R clutch when commanded OFF and exhausts fluid when commanded ON. The clutch PC solenoid 2 regulates the transmission fluid pressure to the 3-5-R 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

P0776

    • 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, 3-5-R clutch is commanded ON
    • For 3rd gear steady state testing:
       - Active the ignition voltage.
       - The Transmission Fluid Temperature (TFT) is greater than or equal to 0°C (32°F).
       - 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 3rd or 5th gear.
    •  For 5th gear steady state testing:
       - Active the ignition voltage.
       - The Transmission Fluid Temperature (TFT) is greater than or equal to 0°C (32°F).
       - 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 3rd or 5th gear.

P0777

    • 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 transmission output shaft speed is greater than 200 RPM.
       - The turbine speed is greater than or equal to 200 RPM, 3-5-R clutch is commanded OFF.
    • For steady state testing:
       - Active the ignition voltage.
       - The Transmission Fluid Temperature (TFT) is greater than or equal to 0°C (32°F).
       - 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

P0776

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 3rd gear steady state testing:

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 4th and 4th 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.3 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 4th and 4th 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.3 commanded pressure is at maximum for 4 seconds.

P0777

Dynamic Test

    • As PC Sol. 2 of 3-5-R clutch commanded pressure is 0 kPa for calibrated amount of time.
    • The obtained gear box slip is equal to or less than 40 RPM for a calibrated amount of time.

Steady State Test:

Fail Case 1 and Fail Case 2 must occur in sequential order, and the transmision is ont at 3rd 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 seconds.

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 P0776 and P0777 are Type A DTCs. Refer to Diagnostic Trouble Code (DTC) Type Definitions and Diagnostic Trouble Code (DTC) List/Type .
    • The TCM commands maximum line pressure.
    • The TCM inhibits TCC.
    • The TCM freezes transmission adaptive functions.

Conditions for Clearing the DIC/DTC

DTCs P0776 and P0777 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. Operate the vehicle in drive with the calculated throttle position greater than 15 percent to obtain 72 km/h (45 mph).
    3. ⇒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 3-5-R clutch assembly for damage.
    7. ⇒If a concern is found in the 3-5-R clutch assembly, repair or replace as necessary.

Component Testing

PC Sol 2 Operation

Operating Conditions

Normal Operation

Stuck OFF

Stuck ON

Steady State Gears 3, 5

3, 5

Neutral

3, 5

Steady State Gears 1, 2, 4, 6

1, 2, 4, 6

1, 2, 4, 6

3, 5

Garage Shift

Park/Neutral to Reverse/Drive

Neutral

1 Gear

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

3, 5

Neutral

3, 5

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

4, 5, 6

4, 5, 6

3, 5

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Control Valve Lower Body and Upper Body Replacement
    •  1-2-3-4 and 3-5 Reverse Clutch Assembly and 4-5-6 Clutch Assembly Removal
    •  Service Fast Learn Adapts
    •  Control Module References for TCM replacement, setup, and programming