GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Yukon - 4WD 🢒 Driveline/Axle 🢒 Transfer Case - NVG 236/246-NP8 (Two Speed Automatic) 🢒 Diagnostic System Check - Instrument Cluster

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.

    2.

  2. The symptom list in Symptoms will determine the correct diagnostic procedure to use.

    3.

  3. The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.

Step

Action

Yes

No

Schematic Reference: Instrument Cluster Schematics

1

Install a scan tool.

Does the scan tool power up?

Go to Step 2

Go to Scan Tool Does Not Power Up in Data Link Communications

2

  1. Turn ON the ignition, with the engine OFF.
  2. Attempt to establish communication with the following control modules:
    3. • Automatic Transfer Case (ATC)
    • Body Control Module (BCM)
    • Electronic Brake Control Module (EBCM)
    • Instrument Panel Cluster (IPC)
    • Powertrain Control Module (PCM) or Engine Control Module (ECM)
    • QS4 Module
    • Real Time Damping (RTD)
    • Sensing and Diagnostic Module (SDM)
    • VSES Module

Does the scan tool communicate with the control modules listed above?

Go to Step 3

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

3

Important: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank Power mode.

  1. Access the Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool.
  2. Rotate the ignition switch through all positions while observing the Ignition Switch Power Mode parameter.

Does the Ignition Switch parameter reading match the ignition switch position for all switch positions?

Go to Step 4

Go to Power Mode Mismatch in Body Control Systems

4

Select the display DTCs function on the scan tool for the following control modules:

  1. Automatic Transfer Case (ATC)
  2. Body Control Module (BCM)
  3. Electronic Brake Control Module (EBCM)
  4. Instrument Panel Cluster (IPC)
  5. Powertrain Control Module (PCM) or Engine Control Module (ECM)
  6. QS4 Module
  7. Real Time Damping (RTD)
  8. Sensing and Diagnostic Module (SDM)
  9. VSES Module

Does the scan tool display any DTCs for the control modules listed above?

Go to Step 5

Go to Symptoms - Instrument Panel, Gages and Console

5

Does the scan tool display any DTCs which begin with a "U"?

Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications

Go to Step 6

6

Does the scan tool display DTC B1000, B1397 or B1398?

Go to Diagnostic Trouble Code (DTC) List in Body Control System

Go to Step 7

7

Does the scan tool display DTC P0562, P0563, P0621, P1637 or P1638?

Go to Diagnostic Trouble Code (DTC) List in Engine Electrical

Go to Diagnostic Trouble Code (DTC) List