SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1311 (TRANSFER CASE - NVG 246-NP8 (TWO SPEED AUTOMATIC))DIAGNOSTIC INFORMATION AND PROCEDURESSERVICE INDICATOR INOPERATIVETEST DESCRIPTION
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Test Description

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Test Description
WARNING: This page is about a different car, the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 Chevrolet Tahoe, 2002 Chevrolet Suburban, and 2002 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The number below refers to the step number on the diagnostic table.

  1. 2:  Determines whether the failure is the result of a faulty transfer case shift control module or the instrument cluster.
Service Indicator Inoperative

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 the ignition ON, with the engine OFF.
  2. Install a scan tool.
  3. Use the scan tool in order to command SERVICE 4WD message ON.
Does the SERVICE 4WD message turn ON?		 Go to Step 3  Go to INSTRUMENT PANEL CLUSTER (IPC) REPLACEMENT in Instrument Panel, Gages, and Console
3 Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement .
Is the repair complete?		 Go to Step 4  -
4
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for allowing the symptom to re-occur.
Does the symptom re-occur?		 Go to Step 2  System OK
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.