GM Service Manual Online
For 1990-2009 cars only

Service Indicator Does Not Light

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. Connect a Scan Tool .
  2. Turn the ignition to RUN, engine OFF.
  3. Use the Scan Tool in order to command the Service indicator (AWD/4WD) lamp On.

Does the Service indicator (AWD/4WD) lamp turn On?

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Go to Step 3

Go to Instrument Cluster Diagnostic System Check

3

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

Is the repair complete?

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Go to Step 4

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4

Reconnect all ATC system components, ensure that all the components are properly mounted.

Have all the ATC components been reconnected and properly mounted?

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Go to Step 5

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5

Clear all the ATC DTCs.

Have all the ATC DTCs been cleared?

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Go to Transfer Case Diagnostic System Check

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