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 P2719:  Clutch Pressure Control (PC) Solenoid 4 System Performance

DTC P2720:  Clutch Pressure Control (PC) Solenoid 4 Control Circuit Low Voltage

DTC P2721:  Clutch Pressure Control (PC) Solenoid 4 Control Circuit High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Clutch PC Solenoid 4 Control

P2720

P2721

P2721

P2719

Clutch PC Solenoid 4 High Side Driver 2

P1833

P1833

P1834

P2719

Clutch PC Solenoid 4 Scan Tool Data

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Clutch PC 4 Sol. CKT Status

OK

Open/Short to Volts

Short to GND

Open/Short to Volts

High Side Driver 2 CKT Status

OK

Open/Short to GND

Open/Short to GND

Short to Volts

Circuit/System Description

The clutch pressure control (PC) solenoid 4 is part of the control solenoid (w/body and TCM) valve assembly and is not serviced separately. The TCM supplies 12 volts to the clutch PC solenoid 4 through the high side driver 2 circuit. The TCM control the clutch PC solenoid 4 through the clutch PC solenoid 4 control circuit. The normally low clutch PC solenoid 4 flows fluid to the 2-6 clutch when commanded ON and exhausts fluid when commanded OFF. The clutch PC solenoid 4 regulates the transmission fluid pressure to the 2-6 clutch.

Conditions for Running the DTC

    • The engine run time is greater than 5 seconds.
    • The clutch PC solenoid 4 is commanded ON or OFF.

Conditions for Setting the DTC

P2719

The TCM detects an internal electrical performance malfunction of the clutch PC solenoid 4 control circuit and the actual 2-6 clutch pressure does not equal the commanded 2-6 clutch pressure for 300 milliseconds.

P2720

The TCM detects an internal low voltage electrical malfunction of the clutch PC solenoid 4 control circuit for 300 milliseconds.

P2721

The TCM detects an internal high voltage electrical malfunction of the clutch PC solenoid 4 control circuit for 300 milliseconds.

Action Taken When the DTC Sets

    • DTC P2719 is a Type C DTC.
    • DTCs P2720 and P2721 are Type A DTCs.
    • The TCM defaults the transmission to a limited shift pattern utilizing 2 forward gears and reverse based on the default detected.
    • The TCM commands maximum line pressure.
    • The TCM freezes transmission adaptive functions.

Conditions for Clearing the DTC

    • DTC P2719 is a Type C DTC.
    • DTCs P2720 and P2721 are Type A DTCs.

Diagnostic Aids

When attempting to set solenoid electrical DTCs, ensure the TCM is warmed up and the transmission is operated in second gear long enough to ensure a 3°C (5°F) increase in TCM substrate temperature. This will place the TCM under the optimal conditions to test solenoid electrical DTCs.

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

Circuit Verification

Perform the following procedure to place the control solenoid (w/body and TCM) valve assembly under the optimal conditions to test solenoid electrical DTCs.

  1. Ensure the transmission fluid temperature is between 50-80°C (122-176°F).
  2. Operate the vehicle in second gear long enough to ensure at least a 3°C (5°F) rise in TCM substrate temperature.

Component Testing

The scan tool data parameter Clutch PC 4 Sol. CKT Status normally displays OK.

If the parameter displays Open/Short to Volts or Short to GND or if the DTC resets, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection and if no concerns are found, replace the control solenoid (w/body and TCM) valve assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Replace the control solenoid (w/body and TCM) valve assembly. Refer to Control Module References for replacement, setup, and programming.
  2. Perform the Service Fast Learn Adapts .