GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Charging System Check ?

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Go to Step  2

Go to Charging System Check

2

  1. Connect a scan tool to the data link connecor (DLC).
  2. Turn the ignition switch to RUN.
  3. Start the engine.
  4. Using the scan tool, monitor the system voltage.

Is the measured votage in the specified range?

Greater than 10.6V

Go to Step  3

Go to Battery Is Undercharged or Overcharged

3

  1. Turn the ignition switch to OFF.
  2. Turn the ignition switch to RUN.
  3. Did the charge indicator turn on, then turn off after the normal bulb check?

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Go to Step  4

Go to Step  11

4

Is the vehicle a Buick?

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Go to Step  13

Go to Step  5

5

  1. Turn the ignition switch to RUN.
  2. Start the engine and keep the engine running at fast idle.
  3. Disconnect the battery themistor connector, located near the battery.
  4. Using a J 39200 digital multimeter (DMM) set to DC volts scale, measure the voltage across the battery terminals.

Is the measured voltage in the specified range?

13-16V

Go to Step 10

Go to Step 11

6

  1. Turn the ignition switch to OFF.
  2. Using a DMM set to DC volts scale, measure the voltage at battery themistor connector terminal A (body horness side).

Is the measured votage in the specified range?

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Go to Step 8

Go to Step 7

7

  1. Check the BATT THER fuse for an open.
  2. If the fuse is open, repair CKT 540 (ORN) Refer to Wiring Repairs in Wiring Systems.

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Go to Step 18

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8

  1. Disconnect the generator connector.
  2. Connect a fused jumper from gernerator harness connector terminalS to ground.
  3. Connect a DM set to ohms scale between the battery themistor connector terminal B (body harness side) and geound

Is the measured resistance in the specified renage?

Less than 5ohms

Go to Step 10

Go to Step 9

9

Repair high risistance or open in CKT 725 (LT BLU).

Is the repair complete:

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Go to Step 18

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10

  1. Check the battery themistor connector for poor terminal contact
  2. If OK, replace the battery themistor.

Is the repaie complete?

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Go to Step 18

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11

  1. Turn the ignition switch to LOCK.
  2. Disconnect the powertrain control module (PCM) connector C2.
  3. turn the ignition switch to RUN.

Did the charge indicator remain on after the nornmal bulb check?

--

Go to Step 12

Go to Step 13

12

Replace the instrument cluster. Refer to Instrument Cluster Replacement in the instrument Panel, Gauges and Console.

Ia the repair complete?

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Go to Step 18

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13

Check CKT 225 (RED) for and open or short to groundl

Is the corcuit OK?

--

Go to Step 15

Go to Step 14

14

Repair the open or short to ground on CKT 225 (RED).

Is the repair complete?

--

Go to Step 18

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15

Check CKT 23 (GRY) for an open or short to ground.

Is the circuit OK?

--

Go to Step 17

Go to Step 16

16

Repair the open or short to gorund on CKT 23 (GRY).

Is the repair complete?

--

Go to Step 18

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17

  1. Check the powertrain control module (PCM) connectors for poor terminal contact.
  2. If OK, replace the PCM. Refer to Powertrain Control Module Replacement/Programming in engine controls - 3.8L OR Powertrain Control Module Replacement/Programming in Engine control - 4.0L , 4.6L.

Is the repair complete?

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Go to Step 18

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18

  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?

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System OK

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