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: Pressure Control (PC) Solenoid 4 System Performance

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

DTC P2721: 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

Typical Scan Tool Data

Clutch PC Solenoid 4

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

PC 4 Sol. CKT Status

OK

Open/Short to Volts

Short to GND

Open/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 transmission control module (TCM) supplies 12 volts to the clutch PC solenoid 4 through the high side driver 1 circuit. The TCM controls the clutch PC solenoid 4 through the clutch PC solenoid 4 control circuit. The normally low clutch PC solenoid 4 flows fluid to the 1-3 clutch when commanded ON and exhausts fluid when commanded OFF. The clutch PC solenoid 4 regulates the transmission fluid pressure to the 1-3 clutch.

Conditions for Running the DTC

    • The engine run time is greater than 5 seconds.
    • The vehicle speed is less than 200 km/h (124 mph) for 5 seconds.
    • The system voltage is 11-18 volts.

Conditions for Setting the DTC

P2719

The TCM detects an internal electrical performance malfunction of the clutch PC solenoid 4 control circuit when the actual 1-3 clutch pressure does not equal the commanded 1-3 clutch pressure for 5 seconds.

P2720

The TCM detects an internal low voltage electrical malfunction of the clutch PC solenoid 4 control circuit for 500 milliseconds.

P2721

The TCM detects an internal high voltage electrical malfunction of the clutch PC solenoid 4 control circuit for 500 milliseconds.

Action Taken When the DTC Sets

    • P2719 is a Type B DTC.
    • 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

    • P2719 is a Type B DTC.
    • 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 long enough to ensure a 3°C (5°F) increase in TCM 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

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

Circuit/System 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 long enough to ensure at least a 3°C (5°F) rise in TCM substrate temperature.

Circuit/System Testing

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

If the parameter displays Open/Short to Volts, 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.

Control Module References for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming.