GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Sonoma Pickup - 2WD 🢒 Driveline/Axle 🢒 Transfer Case - NVG 236/246-NP8 (Two Speed Automatic) 🢒 DTC C0367

Circuit Description

The front axle control circuit consists of a front drive axle clutch solenoid, which is electronically controlled by the transfer case shift control module. This solenoid opens and closes a vacuum control valve allowing vacuum to apply and release a clutch pack inside the front axle housing. The transfer case shift control module determines if the clutch pack has been applied, or released. This determination is based on a signal from the front axle switch, which is mounted on the front axle housing assembly. The front axle is normally locked, or engaged during AUTO 4WD, 4WD HI, and 4WD LO modes. The front axle is unlocked or disengaged only during 2 HI or neutral modes.

Conditions for Setting the DTC
    • The system will try to engage the front axle. If the front axle can not engage the front axle, the system will not attempt to engage the front axle again during that ignition cycle.
    •  The transfer case shift control module reads back the front axle output as a high voltage when a low voltage is expected.

Action Taken When the DTC Sets
    • All shifting for 4WD, AUTO 4WD, and 4WD LO modes will be disabled.
    • SERVICE 4WD indicator will be latched 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 does not exist.
    • A history DTC will clear after 100 consecutive ignition cycle 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. Tests the operation of the front axle switch.

    2.

  2. Tests the front axle control circuit for a short to voltage.

    3.

  3. Helps determine whether the short to voltage is due to a faulty transfer case shift control module or wiring.

Step

Action

Yes

No

Schematic Reference: Transfer Case Control Schematics

1

Did you perform the Transfer Case Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Transfer Case

2

  1. Install a scan tool.
  2. Turn the ignition ON, with the engine ON.
  3. With the scan tool, command the front axle to Locked and Unlocked.

Does the Front Axle Switch status change with each command?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the front drive axle clutch solenoid connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Test the front axle control circuit for a short to voltage. Refer to Circuit Testing in Wiring Systems.

Did you find a short to voltage?

Go to Step 4

Go to Step 5

4

  1. Turn OFF the ignition.
  2. Disconnect the transfer case shift control module.
  3. Turn ON the ignition, with the engine OFF.
  4. Retest the front axle control circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Was the condition found and corrected?

Go to Step 7

Go to Step 6

5

Replace the front axle actuator. Refer to Front Drive Axle Actuator Replacement in Front Axle.

Did you complete the replacement?

Go to Step 7

--

6

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

Did you complete the replacement?

Go to Step 7

--

7
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK