GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

1

Did you review the Battery Description and Operation and the Charging System Description and Operation and perform the necessary inspections?

--

Go to Step 2

Go to Symptoms - Engine Electrical

2

  1. Turn OFF all electrical loads.
  2. Start the engine.
  3. Install a scan tool.
  4. With a scan tool, view the Battery Voltage parameter in the engine data list.

Does the scan tool indicate the voltage is within the specified range?

11.0-15.5 V

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3

  1. Turn OFF the ignition.
  2. Connect a charging system tester to the battery. Follow the manufacturer's instructions.
  3. Operate the engine at 2,500 RPM.
  4. Adjust the carbon pile as necessary in order to obtain the maximum current output.

Is the generator output within 10 A of the specified value?

85 A

Go to Step 9

Go to Step 4

4

  1. Maintain the engine speed at 2,500 RPM and continue to operate the generator at the load test value.
  2. Measure the voltage drop between the generator output terminal and the battery positive terminal.

Is the voltage above the specified value?

0.5 V

Go to Step 6

Go to Step 5

5

  1. Maintain the engine speed at 2,500 RPM and continue to operate the generator at the load test value.
  2. Measure the voltage drop between the battery negative terminal and the generator metal housing.

Is the voltage above the specified value?

0.5 V

Go to Step 7

Go to Step 8

6

Test the battery positive circuit between the generator output terminal and the battery positive terminal for a high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 9

Go to Step 7

7

Repair the high resistance in the ground circuit between the generator housing and the battery negative terminal. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

--

Go to Step 9

--

8

Replace the generator. Refer to Generator Replacement .

Did you complete the repair?

--

Go to Step 9

--

9

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3