GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

  1. Turn the ignition switch from the OFF position to the ON position.
  2. Connect a Scan Tool into the diagnostic link connector (DLC).

Does the scan tool communicate with the body control module (BCM)?

--

Go to Step 3

Go to Step 2

2

Refer to Data Link Communications System Check in Data Link Communications.

Could you establish communication?

--

Go to Step 3

--

3

  1. Place the Scan Tool menu in Body Functions.
  2. Using the scan tool, read the DTCs from the body control module (BCM).

Do any current diagnostic trouble codes exist?

--

Go to Diagnostic Trouble Code (DTC) List/Type

Go to Step 4

4

  1. Remove the Scan Tool from the DLC.
  2. Cycle the ignition from the OFF position to the CRANK position.

Did the SECURITY indicator turn ON then OFF?

--

Go to Step 6

Go to Step 5

5

Does the SECURITY indicator stay ON or FLASH?

--

Go to Theft Deterrent Diagnostic Information

Go to Step 6

6

Are any DTCs in history?

--

Go to Step 7

Go to Step 8

7

  1. Refer to the appropriate DTC table for the history DTC.
  2. Read the diagnostic aids. Read Condition For Setting The DTC.

Did the history DTC set as a current DTC?

--

Go to Diagnostic Trouble Code (DTC) List/Type

--

8

Does the vehicle start and run?

--

System OK

Go to Powertrain On Board Diagnostic (OBD) System Check