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 C0374: General System Malfunction

Circuit/System Description

The transfer case shift control module senses rear slip. After several attempts of applying torque to the front wheels by activating the encoder motor, the transfer case still sees a difference in speed between the front propshaft speed sensor and rear propshaft speed sensor.

Conditions for Running the DTC

    • The ignition is ON.
    • System voltage is 9-18 volts.

Conditions for Setting the DTC

The transfer case shift control module is unable to correct sensed wheel slip for 10 consecutive seconds.

Action Taken When the DTC Sets

    • All shifts to Auto mode are disabled. If the current mode is Auto, the system does not allow any further adaptive events, such as correcting slip.
    • The SERVICE AWD indicator remains illuminated for the remainder of the current ignition cycle.

Conditions for Clearing the DTC

    • A history DTC clears after 100 consecutive ignition cycles without a fault present.
    • Use a scan tool in order to clear history and current DTCs.

Reference Information

Schematic Reference

Transfer Case Control Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Transfer Case Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.