GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1999 🢒 Eighty Eight 🢒 Engine 🢒 Engine Electrical 🢒 Battery Is Undercharged or Overcharged

Step

Action

Value(s)

Yes

No

1

Did you perform the Charging System Check ?

--

Go to Step 2

Go to Charging System Check

2

Check the battery hydrometer.

Is the green dot visible in the hydrometer?

--

Go to Step 7

Go to Step 3

3

Diagnose the battery hydrometer. Refer to Battery Hydrometer Displays Dark or Yellow Dot .

Is the charging system diagnosis complete?

--

Go to Step 4

--

4

Perform the battery load test. Refer to Battery Not Operating Properly .

Did the battery pass the load test?

--

Go to Step 6

Go to Step 5

5

Replace the battery. Refer to Battery Replacement .

Is the repair complete?

--

Go to Step 15

--

6

Check the generator. Refer to Generator Not Operating Properly .

Does the generator operate properly?

--

Go to Step 7

Go to Step 14

7
  1. Disconnect the generator connector.
  2. Turn the ignition switch to ON.
  3. Using a DMM set to DC volts, measure the voltage from the generator connector terminal L to ground.

Is the measured voltage within the specified range?

4-14V

Go to Step 8

Go to Step 11

8

Check CKT 225 (RED) and CKT 23 (GRY) for an intermittent short to ground or open condition.

Are the circuits OK?

--

Go to Step 15

Go to Step 9

9

Repair CKT 225 (RED) or CKT 23 (GRY).

Is the repair complete?

--

Go to Step 15

--

10
  1. Reconnect the generator connector.
  2. Turn all the accessories off.
  3. Run the engine at a fast idle.
  4. Measure the voltage across the battery terminals.

Is the measured voltage within the specified range?

13-16V

Go to Step 15

Go to Step 11

11

Check for an open or short to ground in CKT 225 (RED).

Is the circuit OK?

--

Go to Step 13

Go to Step 12

12

Repair CKT 225 (RED).

Is the repair complete?

--

Go to Step 15

--

13
  1. Check the powertrain control module (PCM) connector C1 for poor terminal contact.
  2. If OK, replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls -- 3.8L.

Is the repair complete?

--

Go to Step 15

--

14

Replace the generator. Refer to Generator Replacement .

Is the repair complete?

--

Go to Step 15

--

15
  1. Make sure any components removed during diagnosis are installed in place and that all connectors are connected.
  2. Repeat the system check. Refer to Charging System Check .

Is the system check complete?

--

System OK

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