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 Valve 2 Control Circuit Low Voltage

DTC P0974: Shift Solenoid Valve 2 Control Circuit High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Shift Solenoid Control

P0973

P0974

P0974

--

Typical Scan Tool Data

Shift Solenoid Valve 2

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Operating Conditions: Engine running, normal operating temperature

Parameter Normal Range: On / Off

Shift Solenoid Control

Off

Off

Off

Circuit/System Description

Shift Solenoid Valve 2 (S2) is installed on the middle valve body. The solenoid turn ON and OFF in response to signals output from the TCM. According to the ON or OFF status of S1 or S2, the 1st gear engine brake operates or the gear shifts into change. As a fail-safe function, if any shift solenoid abnormality occurs, the TCM will disable the current to the solenoids.

Conditions for Running the DTC

P0973

    • The ignition voltage is between 10.2 V and 15.5 V.
    • The engine speed is greater than 400 RPM for 2 seconds.
    • The transmission is not in emergency mode.
    • 10 ms after solenoid output changed.

P0974

    • The ignition voltage is between 10.2 V and 15.5 V.
    • The engine speed is greater than 400 RPM for 2 seconds.
    • The transmission is not in emergency mode.
    • 10 ms after solenoid output changed.

Conditions for Setting the DTC

P0973

The TCM detects an ON signal (12 V) of the S 2 circuit when the S 2 is commanded OFF (0 V) for 100 ms continuously after 5 times.

P0974

The TCM detects an OFF signal (0 V) of the S 2 circuit when the S 2 is commanded ON (12 V) for 100 ms continuously after 5 times.

Action Taken When the DTC Sets

    • DTCs P0973 and P0974 are Type A DTCs.
    • The TCM freezes transmission adaptive functions.
    • The TCM turns OFF all solenoids.
    • The TCM allows the vehicle to operate only in the second gear "R" range after a stop.

Conditions for Clearing the DIC/DTC

    • DTCs P0973 and P0974 are Type A DTCs.
    • The TCM detects an ON signal (12 V) of the S 2 circuit when the S 2 is commanded ON (12 V) for 1 s continuously.
    • The TCM detects an OFF signal (0 V) of the S 2 circuit when the S 2 is commanded OFF (0 V) for 1 s continuously.

Diagnostic Aids

When attempting to set solenoid electrical DTCs, ensure the control solenoid valve assembly is warmed up and the transmission is operated long enough to ensure a 3°C (5°F) increase in temperature. This will place the TCM in 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

Description and Operation

Transmission Component and System Description

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ensure the transmission fluid temperature is between 50 to 80°C (122 to 176°F).
  2. Operate the vehicle in 2nd gear long enough to ensure at least a 3°C (5°F) rise in oil temperature.
  3. Place the gear selector in Reverse for 5 s and then idle vehicle for 5 s.
  4. Observe the scan tool data parameter Shift Solenoid Valve 2. The parameter should display ON.

Circuit/System Testing

Static Test

  1. Ignition OFF, remove the K71 Transmission Control Module (TCM).
  2. Test for 11-15 Ω between the Shift Solenoid Control circuit terminal 2 (X2) and ground.
  3. If not within the specified range, test the wiring harness for internal short, or interruption. If the circuit test normal, replace the Q32B Shift Solenoid (SS) Valve.
  4. Test for infinite resistance between each terminal and the Shift Solenoid Control circuit terminal 2 (X2).
  5. If less than the specified range, replace the wiring harness.
  6. If all circuits test normal, test or replace the Q32B Shift Solenoid (SS) Valve. Verify the DTC does not reset.
  7. If the DTC resets, replace the K71 Transmission Control Module (TCM).

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    • Control valve body replacement. Refer to Control Valve Body Replacement for replacement, setup and programming.
    • TCM, refer to Control Module References for replacement, setup and programming.
       ⇒Perform the Transmission Adaptive Functions.
    • Wiring harness, refer to Automatic Transmission Wiring Harness Replacement for replacement