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 P07A9: Transmission Friction Element 4 Stuck On

Typical Scan Tool Data

1-3 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 4 Slip Speed

0 RPM

0-6,000 RPM

0 RPM

Clutch 4 Status

Applied

Released

Released

Circuit/System Description

The hybrid powertrain control module (HPCM) monitors the Clutch Slip for each Hybrid Trans. Mode Commanded state. This DTC detects no clutch slip when the 1-3 clutch is commanded OFF, indicating a stuck or welded clutch condition.

Conditions for Running the DTC

    • The 1-3 clutch is the primary off-going clutch.
    • The Hybrid Trans. Mode Commanded is not gear 1 or gear 3.
    • The Calc. Trans Input Speed is greater than 250 RPM.

Conditions for Setting the DTC

Fail Case 1

The 1-3 clutch is commanded OFF for 3 seconds and the HPCM detects the 1-3 clutch slip speed is less than 100 RPM for 0.25 seconds, when commanded OFF in EVT 1 mode.

Fail Case 2

The 1-3 clutch is commanded OFF for 3 seconds and the HPCM detects the 1-3 clutch slip speed is less than 80 RPM for 0.25 seconds, when commanded OFF in EVT 2 mode.

Action Taken When the DTC Sets

P07A9 is a Type B DTC.

Conditions for Clearing the DTC

P07A9 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 EVT 1 through 4th gear while observing the 1-3 Clutch Slip parameter. Stop the vehicle and turn the ignition OFF for 30 seconds. Perform this action 2 times. The 1-3 Clutch Slip parameter display should be greater than 0 RPM when the 1-3 Clutch Status parameter displays Released.
  3. If any other transmission DTCs are set, diagnose those first.
    If the DTC P07A9 resets, go to Component Testing.

Component Testing

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

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    • 1-3 Clutch Housing Overhaul for 1-3 clutch assembly, replacement or repair.
    •  Control Valve Lower Body and Upper Body Replacement for lower valve body assembly repair or 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.
    •  Control Module References for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming.