GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC C Sierra - 2WD 🢒 Driveline/Axle 🢒 Transfer Case - NVG 263-NP1 (Selectable) 🢒 DTC C0362

Circuit Description

The 4WD low signal circuit is used to notify the powertrain control module (PCM) that the vehicle is in 4WD low range. The PCM supplies 12 V to this circuit. The transfer case shift control module grounds this circuit when the vehicle is in 4WD low range.

This DTC detects a transfer case shift control module problem, or a short to voltage on the 4WD low signal circuit.

Conditions for Setting the DTC
    • After the transfer case shift control module grounds the 4WD low signal circuit and reads back a high voltage, the DTC is set. The system will not attempt again during that ignition cycle.
    • The transfer case shift control module reads back a high voltage when a low voltage is expected on the 4 low signal circuit.

Action Taken When the DTC Sets
    • The transmission shift point may be affected.
    • The SERVICE 4WD indicator lamp will be commanded on for the remainder of the current ignition cycle.

Conditions for Clearing the DTC
    • The transfer case shift control module will clear the DTC if the condition for setting the DTC no longer exits.
    • A history DTC will clear after 100 consecutive ignition cycles without a fault present.
    • History DTCs can be cleared using a scan tool.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests the 4WD low signal circuit for voltage.

    2.

  2. This step tests the 4WD low signal circuit for a short to voltage.

    3.

  3. This step tests the 4WD low signal circuit for an open or high resistance.

    4.

  4. This step repairs the 4WD low signal circuit for a short to voltage.

Step

Action

Yes

No

Schematic Reference: Transfer Case Control Schematics

1

Was the Transfer Case Diagnostic System Check performed?

Go to Step 2

Go to Diagnostic System Check - Transfer Case

2

  1. Turn OFF the ignition.
  2. Disconnect the transfer case shift control module.
  3. Connect a test lamp between the 4WD low signal circuit and ground.
  4. Turn ON the ignition with the engine OFF.

Does the test lamp illuminate?

Go to Step 3

Go to Step 4

3

  1. Turn OFF the ignition.
  2. Disconnect the powertrain control module.
  3. Turn ON the ignition with the engine OFF.

Does the test lamp continue to illuminate?

Go to Step 5

Go to Step 7

4

Test the 4WD low signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 6

5

Repair the 4WD low signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 8

--

6

Replace the powertrain control module. Refer to Powertrain Control Module Replacement in Engine Controls 4.8 L, 5.3 L, and 6.0 L, or Powertrain Control Module Replacement in Engine Controls 8.1 L.

Did you complete the replacement?

Go to Step 8

--

7

Replace the transfer shift case control module. Refer to Transfer Case Shift Control Module Replacement .

Did you complete the replacement?

Go to Step 8

--

8
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Setting the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK