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 P0973: Shift Solenoid (SS) 1 Control Circuit Low Voltage

DTC P0974: Shift Solenoid (SS) 1 Control Circuit High Voltage

DTC P0976: Shift Solenoid (SS) 2 Control Circuit Low Voltage

DTC P0977: Shift Solenoid (SS) 2 Control Circuit High Voltage

DTC P0979: Shift Solenoid (SS) 3 Control Circuit Low Voltage

DTC P0980: Shift Solenoid (SS) 3 Control Circuit High Voltage

DTC P0982: Shift Solenoid (SS) 4 Control Circuit Low Voltage

DTC P0983: Shift Solenoid (SS) 4 Control Circuit High Voltage

DTC P0985: Shift Solenoid (SS) 5 Control Circuit Low Voltage

DTC P0986: Shift Solenoid (SS) 5 Control Circuit High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Signal

P0973, P0976, P0979, P0982, P0985

P0973, P0976, P0979, P0982, P0985

P0974, P0977, P0980, P0983, P0986

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Circuit/System Description

The five shift solenoids (SS) are installed directly in the transmission valve body (V/B). The vehicle gear range is determined by various combinations of the shift solenoid states. Each shift solenoid is controlled (driven) by the TCM.

Conditions for Running the DTC

    • The engine is running.
    • The transmission is not in Emergency Mode.

Conditions for Setting the DTC

The TCM detects that the shift solenoid actual state doesn’t match the commanded state for 0.5 second.

Action Taken When the DTC Sets

P0973, P0976, P0977, P0982, and P0983

    • Type A DTC
    • The transmission will operate in 5th gear in D or M range, 2nd gear in L range.

P0974, P0985, and P0986

    • Type A DTC
    • The transmission will operate in 5th gear in D or M range, 2nd gear in L range.
    • The engine torque is limited to 185 N·m.

P0979

    • Type A DTC
    • The transmission will operate in 5th gear in D or M range, 4th gear in L range.

P0980

    • Type A DTC
    • The transmission will operate in 3rd gear in D or M range.

Conditions for Clearing the DTC

DTC P0973, P0974, P0976, P0977, P0979, P0980, P0982, P0983, P0985, and P0986 are Type A DTC’s

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

    •  Automatic Transmission Inline Harness Connector End View
    •  Automatic Transmission Internal Connector End Views
    •  Automatic Transmission Related Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

    •  Diagnostic Trouble Code (DTC) Type Definitions
    •  Diagnostic Trouble Code (DTC) List/Type

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

  1. Ignition ON, observe the DTC information with a scan tool.
  2. Record Freeze Frame and Failure Records.
  3. Clear DTC’s.
  4. Operate the vehicle under the conditions observed in the Failure Records.
  5. Observe the DTC information with the scan tool. Verify that the DTC does not set.

Circuit/System Testing

  1. Ignition OFF, disconnect the 22-way automatic transmission (AT) wiring harness connector (C2) at the TCM.
  2. Test for 11-24 ohms of resistance between the shift solenoid control circuit terminal (harness side) and ground.
  3. If not within the specified range
    • Remove the appropriate solenoid and test for 11-24 ohms of resistance.
         ⇒If not within the specified range, replace the valve body assembly.
    • Replace the AT wiring harness, refer to Wiring Harness Removal procedure and Wiring Harness Installation procedure.
  4. At the TCM, connect a test lamp between the shift solenoid high control circuit and the ground.
  5. Command the shift solenoid ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
  6. If the test lamp does not follow the commanded states, replace the TCM, refer to Transmission Control Module Removal procedure and Transmission Control Module Installation procedure.

Component Testing

Test the shift solenoid, at 20°C, for 11-16 ohms of resistance between the control circuit terminal and its case ground.

If not within the specified range, replace the solenoid.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.