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DTC P0973 or P0974

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 1 Control Circuit Low Voltage

DTC P0974: Shift Solenoid Valve 1 Control Circuit High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Shift Solenoid Valve 1 Control

P0973

P0974

P0974

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Typical Scan Tool Data

Shift Solenoid Valve 1 Control Circuit High Voltage Test Status

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Operating Conditions: Engine running, normal operating temperature

Parameter Normal Range: OK

Shift Solenoid Valve 1 Control

--

--

Fault or Malfunction

Shift Solenoid Valve 1 Control Circuit Open Test Status

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Operating Conditions: Engine running, normal operating temperature

Parameter Normal Range: OK

Shift Solenoid Valve 1 Control

-

Fault or Malfunction

-

Shift Solenoid Valve 1 Control Circuit Low Voltage Test Status

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Operating Conditions: Engine running, normal operating temperature

Parameter Normal Range: OK

Shift Solenoid Valve 1 Control

Fault or Malfunction

--

--

Circuit/System Description

The shift solenoid (SS) valve 1 is part of the control solenoid valve assembly which has no serviceable components. SS valve 1 is a normally closed (NC) ON/OFF solenoid and is controlled by the transmission control module (TCM) through a low side driver. When the SS valve 1 is energised (ON), SS 1 fluid pressure is directed to the clutch select valve. Power to the SS 1 is supplied by the TCM through a high side driver (HSD). The HSD protects the circuit and components from excessive current flow. If excessive current flow is detected, the HSD will turn OFF. When the fault is corrected the HSD will reset.

Conditions for Running the DTC

P0973 or P0974

    • The engine speed is 400 RPM or greater for 5 seconds.
    • The ignition voltage is 9.0 volts or greater.

Conditions for Setting the DTC

P0973

The control solenoid valve assembly detects an internal low voltage electrical malfunction of the SS Valve 1 control circuit for 2 seconds.

P0974

The control solenoid valve assembly detects an internal high voltage electrical malfunction of the SS Valve 1 control circuit for 2 seconds.

Action Taken When the DTC Sets

P0973

    • DTC P0973 is a Type A DTC.
    • The TCM freezes transmission adaptive functions.
    • The TCM commands maximum line pressure.
    • The TCM limits the transmission to 2nd gear and reverse.
    • The TCM inhibits the Tap Up/Tap Down function.
    • The TCM inhibits manual shifting of forward gears.

P0974

    • DTC P0974 is a Type B DTC.
    • The TCM inhibits 1st gear.

Conditions for Clearing the DIC/DTC

    • DTC P0973 is a Type A DTC.
    • DTC P0974 is a Type B DTC.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

    •  Component Connector End Views
    •  Inline Harness Connector End Views

Description and Operation

    •  Transmission General Description
    •  Transmission Component and System Description
    •  Electronic Component Description

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

Special Tools

DT-48616-10 Adapter Harness

For equivalent regional tools, refer to Special Tools .

Circuit/System Verification

  1. Operate the vehicle in 2nd gear long enough to ensure at least a 3°C (5°F) rise in TCM temperature.
  2. Place the gear selector in Reverse for 5 seconds and then idle vehicle for 5 seconds. Verify with a scan tool, the following test status parameters displays OK.
  3. • Shift Solenoid Valve 1 Control Circuit Open Test Status
    • Shift Solenoid Valve 1 Control Circuit High Voltage Test Status
    • Shift Solenoid Valve 1 Control Circuit Low Voltage Test Status
  4. After performing the above steps, verify that the DTC does not reset by operating the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions you observe from the Freeze Frame/Failure Records data. If the vehicle passes the Circuit/System Verification procedure, then STOP. Do not perform the Circuit/System Testing or Component Testing as this may result in an unnecessary part replacement. Refer to Testing for Intermittent Conditions and Poor Connections .

Circuit/System Testing

    Note: You must perform the Circuit/System Verification first.

  1. Ignition OFF, remove the Q8 control solenoid valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Replacement .
  2. Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection .
  3. Place the Q8 control solenoid valve assembly on a clean work surface near the transmission assembly.
  4. Connect DT-48616-10 harness between the vehicle wire harness X1 14-way transmission electrical connector, and the Q8 control solenoid valve assembly.
  5. Ignition ON, verify with a scan tool the following test status parameters display, OK.
  6. • Shift Solenoid Valve 1 Control Circuit Open Test Status
    • Shift Solenoid Valve 1 Control Circuit High Voltage Test Status
    • Shift Solenoid Valve 1 Control Circuit Low Voltage Test Status
    If any test status parameter displays Fault or Malfunction, replace the Q8 control solenoid valve assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

       Note: Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection .

    • Refer to Control Module References for control solenoid valve assembly replacement, set-up, and programming.
    • Perform the Transmission Adaptive Values Learn following all transmission related repairs.
   


© Copyright Chevrolet. All rights reserved
   


© Copyright Chevrolet. All rights reserved