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 C0396 01: Incremental Position Sensor Circuit Short to Battery

DTC C0396 02: Incremental Position Sensor Circuit Short to Ground

DTC C0396 04: Incremental Position Sensor Open Circuit

DTC C0396 05: Incremental Position Sensor Circuit Short to Battery or Open

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Invalid

Incremental Position Sensor Circuit

DTC C0396 02

DTC C0396 04

DTC C0396 05

DTC C0396 01

DTC C0396 05

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Circuit/System Description

The transfer case shift control module has an input from incremental sensor which shows the speed, transfer case range, and direction of the transfer case mode or range shifts. The incremental sensor is an integral part of the transfer case actuator and can not be replaced independently. The incremental sensor indicates important information about the speed and direction of the transfer case two/four wheel drive actuator position. This sensor receives an 8-volt reference signal from the transfer case control module and gets this data back via the transfer case incremental impulse signal, as well as the incremental direction signal in order to know the current location.

Conditions for Running the DTC

    • The ignition is ON.
    • System voltage is 10.5-18 volts.

Conditions for Setting the DTC

    • The transfer case control module sees a incremental 8-volt reference signal that is not between 1.5-8.2 volts indicating a short to ground or open if low and a short to voltage if high.
    • The module does not receive a incremental impulse signal voltage between 0.5-4.6 volts.
    • The incremental low reference circuit has an open or high resistance.

Action Taken When the DTC Sets

    • All shifting is disabled until the condition no longer exists.
    • The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle.

Conditions for Clearing the DTC

    • The transfer case shift control module clears the DTC if the condition for setting the DTC is not currently present.
    • A history DTC clears after 40 consecutive warm up cycles without a fault present.
    • History DTCs can be cleared using a scan tool.

Reference Information

Schematic Reference

Transfer Case Control Schematics

Connector End View Reference

Transfer Case Control Connector End Views

Electrical Information Reference

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

DTC Type Reference

DTC Symptom Description

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Diagnostic Aids

An open, high resistance, or short to voltage on the incremental sensor direction signal circuit will cause this DTC to set. If the sensor is determined to be bad the entire transfer case actuator will have to be replaced as the incremental sensor is part of the actuator and can not be replaced independently.

Circuit/System Testing

The incremental sensor impulse signal circuit, incremental direction signal circuit, incremental sensor low reference circuit, and the 8-volt reference circuit will need to be check for a short to ground, open, high resistance, and a short to voltage using the following steps:

  1. Disconnect the connector at the transfer case actuator and check the 8-volt reference signal on pin G at the transfer case actuator with a DMM, ignition on, the voltage should read 7.8-8.2 volts.
  2. If the voltage does not read within the specifications then check the 8-volt reference circuit for a short to voltage, open, high resistance, or short to ground. If the circuit checks good and the voltage is out of range replace the transfer case control module, program, and perform the motor learn procedure. If the circuit checks good continue to next step.
  3. At the transfer case actuator, with a jumper harness short the 8-volt reference circuit pin G to the incremental impulse signal pin E and note the voltage on the scan tool data display.
  4. If the voltage does not read 7.8-8.2 volts check the incremental impulse signal circuit for and open, high resistance, short to ground, or short to voltage. If the circuit checks good then go to the next step.
  5. Check the incremental direction circuit for an open, short to ground, high resistance, or a short to voltage by probing pin F at the transfer case actuator and pin 14 and transfer case control module connector X2.
  6. If all circuit test good replace the transfer case actuator and perform the motor learn procedure.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Control Module References for TCSCM replacement, setup, and programming
    •  Transfer Case High/Low Clutch Reset
    •  Transfer Case Two/Four Wheel Drive Actuator Replacement