GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Check the vehicle for Diagnostic Trouble Codes (DTCs).

Are any DTCs present?

--

Go to Diagnostic Trouble Code (DTC) List in Engine Controls

Go to Step 2

2

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

Is the SERVICE ENGINE SOON indicator on?

--

Go to Step 3

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

3

  1. Check for a short to ground in CKT 419.
  2. If OK, replace the instrument cluster. Refer to Instrument Cluster Replacement .

Has the repair been made and the system rechecked?

--

System OK

--