GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2000 🢒 Yukon Denali 🢒 Driveline/Axle 🢒 Transfer Case - NVG 246-NP8 (Two Speed Automatic) 🢒 DTC B0768 Service Indicator Circuit High

Object Number: 562195 Size: MF
Transfer Case Control Components
Transfer Case Control Schematics

Circuit Description

The transfer case shift control module controls the SERVCE indicator (AWD/4WD) lamp, located in the instrument cluster, by grounding the SERVICE Indicator lamp control circuit. Voltage to the lamp is supplied via a common GAUGE Fuse, which feeds all of the gauges in the instrument cluster.

Conditions for Setting the DTC

After the transfer case shift control module commands the lamp on, the module senses a voltage greater than 7 V on the SERVICE Indicator lamp output circuit.

Conditions for Clearing the DTC
    • The transfer case shift control module will clear the DTC if the condition for setting the DTC no longer exists.
    • A history DTC will clear after 100 consecutive ignition cycles without a fault present.
    • Use a scan tool in order to clear history DTCs.

Test Description

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

  1. Look for the visual operation of the SERVICE indicator lamp. Command both the ON and OFF states.

    2.

  2. Tests the operation of the SERVICE indicator lamp circuit.

    3.

  3. Tests the SERVICE indicator lamp output circuit for an open, short to ground or high resistance.

DTC B0768 SERVICE Indicator High

Step

Action

Value(s)

Yes

No

1

Was the Transfer Case Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check

2

  1. Install a scan tool.
  2. Turn the ignition ON with the engine OFF.
  3. With a scan tool, command the SERVICE Indicator control ON and OFF.

Does the SERVICE Indicator lamp turn ON and OFF with each command?

--

Go to Testing for Electrical Intermittents

Go to Step 3

3

  1. Disconnect the transfer case shift control module.
  2. Using a fused jumper harness, connect the SERVICE indicator lamp control circuit to ground.

Does the SERVICE indicator lamp turn ON?

--

Go to Step 6

Go to Step 4

4

Test the SERVICE indicator lamp control circuit for an open, short to ground, or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Was the condition found and corrected?

--

Go to Step 7

Go to Step 5

5

Remove the instrument cluster for repair. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.

Is the repair complete?

--

Go to Step 7

--

6

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

Is the repair complete?

--

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