GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1997 🢒 Century 🢒 Engine 🢒 Engine Electrical 🢒 Battery Is Undercharged or Overcharged

Battery Is Undercharged or Overcharged Chevrolet/Oldsmobile

Step

Action

Value(s)

Yes

No

DEFINITION: Battery Is Undercharged Or Overcharged.

1
  1. Disconnect the generator connector.
  2. Turn the ignition switch to RUN.
  3. Attach a scan tool to the DLC.
  4. Clear any DTC.
  5. Select Misc. Tests, ENG Outputs, and GEN L Terminal.
  6. Command the generator ON.
  7. Using a digital multimeter, measure the voltage from the generator connector circuit 225 to ground.

Does the DMM show battery voltage?

B+

Go to Step 3

Go to Step 2

2
  1. Check for a poor connection or open in circuit 225.
  2. If OK, service the PCM. Refer to Engine Controls.

Has the repair/service been made and the system rechecked?

--

System OK

--

3

Using a digital multimeter, measure the voltage from the generator BAT terminal to ground.

Does the DMM show battery voltage?

B+

Go to Step 5

Go to Step 4

4

Repair the open in circuit 2 to the generator BAT terminal.

Has the repair been made and the system rechecked?

--

System OK

--

5
  1. Reconnect the generator connector.
  2. Turn all accessories off.
  3. Run the engine at a fast idle.
  4. Using a DMM, measure the voltage across the battery.

Is the reading within the specified range?

13 - 16 V

Go to Step 7

Go to Step 6

6

Replace the generator. Refer to Generator Replacement.

Has the replacement been made and the system rechecked?

--

System OK

--

7
  1. Load test the generator. Refer to Generator Electrical Test.
  2. If the generator tests OK, replace the battery. Refer to Battery Replacement.

Has the load test/replacement been made and the system rechecked?

--

System OK

--

Battery Is Undercharged or Overcharged Pontiac

Step

Action

Value(s)

Yes

No

DEFINITION: Battery Is Undercharged Or Overcharged

1
  1. Disconnect the Generator connector.
  2. Set the Ignition Switch to RUN.
  3. Attach a scan tool to the DLC.
  4. Clear any DTC.
  5. Select Misc Tests, Eng Outputs, and Gen L Term.
  6. Command the Gen ON.
  7. Use a DMM to measure the voltage from the generator connector terminal L to ground.

Is B+ measured?

B+

Go to Step 2

Go to Step 5

2

Using a DMM, measure the voltage from the Generator BATTERY terminal to ground.

Is B+ measured?

B+

Go to Step 3

Go to Step 6

3
  1. Reconnect the Generator connector.
  2. Be sure all accessories are OFF.
  3. Run the engine at fast idle.
  4. Using a DMM, measure the voltage across the Battery.

Is the voltage within specified values?

13-16 V

Go to Step 4

Go to Step 7

4
  1. Load Test the Generator. Refer to ENGINE CONTROLS.
  2. If OK, replace the Battery.

Has the repair been made, and the system rechecked?

--

System OK

--

5
  1. Check for a poor connection or open in CKT 225.
  2. If OK, Service the PCM, refer to ENGINE CONTROLS.

Has the repair been made, and the system rechecked?

--

System OK

--

6

Repair open in CKT 2 or Fusible Link to the Generator BATTERY terminal.

Has the repair been made, and the system rechecked?

--

System OK

--

7

Replace the Generator.

Has the repair been made, and the system rechecked?

--

System OK

--

Battery Is Undercharged or Overcharged Buick

Step

Action

Value(s)

Yes

No

DEFINITION: Undercharged Or Overcharged

1
  1. Disconnect the generator connector.
  2. Set the ignition switch to RUN.
  3. Attach a scan tool to the DLC.
  4. Clear any DTC.
  5. Select the following:
    6. • Select Misc Tests.
    • Select Eng Outputs.
    • Select Gen L Term.
  6. Command the generator ON.
  7. Using a DMM, measure the voltage from the generator connector terminal L to ground.

Is the measured voltage within the specified range?

9-14 V

Go to Step 2

Go to Step 5

2

Using a DMM, measure the voltage from the generator BATTERY terminal to ground.

Is the measured voltage within the specified range?

9-14 V

Go to Step 3

Go to Step 6

3
  1. Reconnect the generator connector.
  2. Turn all the accessories OFF.
  3. Run the engine at a fast idle.
  4. Using a DMM, measure the voltage across the battery.

Is the measured voltage within the specified range?

13-16 V

Go to Step 4

Go to Step 7

4
  1. Load test the generator. Refer to Charging System in Section 6D3.
  2. If OK, replace the battery. Refer to Battery 6D1.

Has the repair/replacement been made and the system rechecked?

--

System OK

--

5
  1. Using a DMM, check for a poor connection or an open in circuit 225.
  2. If OK, service the PCM. Refer to Engine Controls in Section 6E.

Has the repair been made and the system rechecked?

--

System OK

--

6

Repair the open in circuit 2 or the fusible link to the generator BATTERY terminal.

Has the repair been made and the system rechecked?

--

System OK

--

7

Replace the generator. Refer to Charging System 6D3.

Has the replacement been made and the system rechecked?

--

System OK

--