GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you test the vehicle for Diagnostic Trouble Codes (DTC)?

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Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls 3.1

or

Powertrain On Board Diagnostic (OBD) System Check in Engine Controls 3.8

2

  1. Disconnect the Powertrain Control Module (PCM) connector C2.
  2. Turn the ignition switch to the RUN position.

Does the CHANGE OIL SOON indicator illuminate?

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Go to Step 3

Go to Step 4

3

  1. Inspect for a short to ground in CKT 803.
  2. If OK, replace the instrument cluster. Refer to Instrument Cluster Replacement .
  3. Inspect the system.

Is the repair complete?

--

System OK

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4

  1. Connect a fused 3 amp jumper between the PCM harness connector C2 terminal 36 and ground.
  2. Turn the ignition switch to the RUN position.

Does the CHANGE OIL SOON indicator illuminate?

--

Go to Powertrain Control Module Controlled Warning Lamps Description in Engine Controls - 3.1

or

Powertrain Control Module Controlled Warning Lamps Description in Engine Controls - 3.8

Go to Step 5

5

Inspect for a poor connection or an open in CKT 803.

Does a poor connection or an open exist in CKT 803?

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Go to Step 6

Go to Step 7

6

  1. Repair the poor connection or the open in CKT 803.
  2. Inspect the system.

Is the repair complete?

--

System OK

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7

  1. Inspect the warning indicator bulb and the bulb connection.
  2. If OK, replace the instrument cluster. Refer to Instrument Cluster Replacement .
  3. Inspect the system.

Is the repair complete?

--

System OK

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