GM Service Manual Online
For 1990-2009 cars only

Service Indicator Stays On When Key Is On

Step

Action

Value(s)

Yes

No

1

Was the Transfer Case Diagnostic System Check performed?

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Go to Step 2

Go to Transfer Case Diagnostic System Check

2

  1. Install the Scan Tool .
  2. Turn the ignition ON, engine OFF.
  3. Use a Scan Tool in order to command the SERVICE Indicator (AWD/4WD) lamp OFF.

Does the SERVICE indicator (AWD/4WD) lamp turn off?

--

Go to Step 3

Go to Step 4

3

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

Is the action complete?

--

Go to Step 5

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4

Replace the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges, and Console.

Is the repair complete?

--

Go to Step 5

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5

  1. Properly mount and reconnect all previously disconnected components.
  2. Turn the ignition ON, engine OFF.
  3. Using the scan tool, clear all DTCs.

Is the action complete?

--

Go to Transfer Case Diagnostic System Check

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