GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Blazer - 4WD - RHD 🢒 Body and Accessories 🢒 Wiring Systems 🢒 Service Indicator Always On

Test Description

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

  1. Determines whether the failure is the result of a faulty transfer case shift control module or the instrument cluster.

SERVICE 4WD Message Always On

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. Turn the ignition ON, with the engine OFF.
  2. Install a scan tool.
  3. Use the scan tool in order to command the SERVICE 4WD Message OFF.

Does the SERVICE 4WD Message turn OFF?

--

Go to Step 3

Go to Instrument Cluster Replacement

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