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 Descriptor

DTC P07A3: Transmission Friction Element 1 Stuck On

Typical Scan Tool Data

Hybrid Low, 1-2 Clutch Reference

Parameter

Commanded ON

Commanded OFF

Stuck/Welded When Commanded OFF

Operating Conditions: Vehicle speed 0-50 MPH

Parameter Normal Range: 0-6,000 RPM

Clutch 1 Slip Speed

0 RPM

0-6,000 RPM

0 RPM

Clutch 1 Status

Applied

Released

Released

Circuit/System Description

The hybrid powertrain control module (HPCM) monitors the Clutch Slip parameters for each Hybrid Trans. Mode Commanded state. This DTC detects no clutch slip when the hybrid low, 1-2 clutch is commanded OFF, indicating a stuck or welded clutch condition.

Conditions for Running the DTC

    • Hybrid low, 1-2 clutch is the primary off-going clutch.
    • The hybrid low, 1-2 clutch is commanded OFF for 3 seconds and the HPCM detects the clutch 1 slip speed is less than 30 RPM for 4.5 seconds, when commanded OFF.

Conditions for Setting the DTC

The hybrid low, 1-2 clutch is commanded OFF for 3 seconds and the HPCM detects the clutch 1 slip speed is less than 30 RPM for 4.5 seconds, when commanded OFF.

Action Taken When the DTC Sets

P07A3 is a Type B DTC.

Conditions for Clearing the DTC

P07A3 is a Type B DTC.

Diagnostic Aids

When attempting to set transmission performance DTCs, observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions. Ensure the transmission fluid level is correct and there are no leaks. If there are any other transmission DTCs set, diagnose those first.

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.

Circuit/System Verification

  1. Clear the DTC.
  2. Operate the vehicle from 1st through 4th gear while observing the Clutch 1 Slip Speed parameter. Stop the vehicle and turn the ignition OFF for 30 seconds. Perform this action 2 times. The Clutch 1 Slip Speed parameter should display greater than 0 RPM when the Clutch 1 Status parameter displays Released.
  3. If any other transmission DTCs are set, diagnose those first.
    If the DTC P07A3 resets, go to Component Testing.

Component Testing

  1. Perform the Line Pressure Check.
  2. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test.
  3. If a concern is found, replace the control solenoid (w/body and TCM) valve assembly.
  4. Inspect the trans fluid pump ball check valve for possible sticking or damage.
  5. If you found a concern with this check ball, repair the concern.
  6. Inspect the hybrid low, 1-2 clutch boost valve assembly for sticking or damage.
  7. If you found a concern with the hybrid low, 1-2 clutch regulator valve, repair or replace the valve or valve body.
  8. Inspect the hybrid low, 1-2 clutch for a stuck On or damaged condition.
  9. If you found a hybrid low, 1-2 clutch concern, repair or replace the hybrid low, 1-2 clutch assembly as necessary.

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.
    • Hybrid Low, 1-2 Clutch Piston Removal and Hybrid Low, 1-2 Clutch Piston Installation for hybrid low, 1-2 clutch repair or replacement.
    •  Control Valve Lower Body and Upper Body Replacement for lower valve body assembly replacement.
    • Perform the valve body inspection procedure, refer to Control Solenoid Valve and Transmission Control Module Assembly Inspection. If the inspection procedure indicates to replace the valve body, refer to Control Valve Lower Body and Upper Body Replacement.