GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

1

  1. Start the engine.
  2. Connect the voltmeter (set at DC scale) between the generator L terminal and ground.

Is the voltage above the specified value?

8.0 V

Go to Step 2

Go to Step 3

2

Connect the voltmeter to the generator BAT terminal.

Is the voltage above the specified value?

More than 8.0 V

Go to Step 4

Go to Step 5

3

  1. Inspect for an open or a poor connection in CKT 225 between generator terminal L and PCM connector C2 terminal 35.
  2. Repair as needed.

Are the repairs complete?

--

System OK

--

4

  1. Run the engine at fast idle.
  2. Turn all of the accessories off.
  3. Connect the voltmeter (DC scale) across the battery terminals.

Is the voltage within the specified range?

13.3--15.5 V

Go to Step 6

Go to Step 7

5

  1. Inspect between the generator BAT terminal and the battery for an open in CKT1.
  2. Repair as needed.

Are the repairs complete?

--

System OK

--

6

  1. Test the generator. Refer to Charging System Diagnosis .
  2. Load test the battery. Refer to Battery Load Test .
  3. Repair as needed.

Are the repairs complete?

--

System OK

--

7

Replace the generator. Refer to Generator Replacement .

Are the repairs complete?

--

System OK

--