GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

Caution: Refer to Battery Disconnect Caution in the Preface section.

Important: The battery test using the J 42000 requires correct connections to the battery terminals. A failure to obtain the correct connections during the test may result in a failed test on a good battery.

Follow these instructions in order to avoid an incorrect diagnosis because of connections:

    • If testing the vehicle with the battery cables still connected, wiggle the J 42000 clips on the terminal bolt. This may cut through any coating or through any oxidation that may be present on the bolt.
        Even new bolts contain a protective coating that may insulate or cause a resistance in the test circuit.
    • If correct connections to the battery terminal bolts in the vehicle are in doubt, perform the following steps:
        1. Disconnect the negative battery cable.
        2. Disconnect the positive battery cable.
        3. Install the test adapters on the terminals.
        4. Follow the instructions for testing a removed battery.
    • If the tester displays a REPLACE BATTERY result for a battery tested in the vehicle with the battery cables connected, perform the following steps:
        1. Disconnect the negative battery cable.
        2. Disconnect the positive battery cable.
        3. Install the tester adapters.
        4. Follow the instructions for testing a removed battery.
        5. Replace the battery only if the second test shows a REPLACE BATTERY result.

Use the test code from the second test for any warranty purposes.

    • Use the correct terminal adapters.
        Do not use any common bolts or a combination of bolts, of nuts, and of washers as adapters when testing the battery.
        Use the test adapters that are provided with the J 42000 or P/N 12303040 terminal adapters. If the adapters that are provided with the J 42000 require replacement, use P/N 12303040. Any other adapter may not contact the correct areas of the battery terminal, causing a resistance that may result in an invalid battery test result.

Important: Always write the test code displayed by the tester on the repair order for any warranty purposes. The number is a unique code that describes the test data for a particular battery at a particular time. The test code may occasionally repeat when you retest the same battery. More often, each test will result in a different code.

Step

Action

Value(s)

Yes

No

1

Inspect the battery for a cracked, broken, or damaged case, which may be indicated by battery acid leakage.

Is the battery OK?

--

Go to Step  2

Go to Step  19

2

Compare the Cold Cranking Amperage (CCA) and the reserve capacity of the battery to the original battery or to the original equipment specification. Refer to Battery Usage .

Does the battery meet or exceed the specifications?

--

Go to Step  3

Go to Step  19

3

Does the hydrometer display a yellow dot?

--

Go to Step  4

Go to Step  5

4

Tap the hydrometer lightly on top with the handle of a small screwdriver in order to dislodge any air bubbles inside the battery.

Does the hydrometer still display a yellow dot?

--

Go to Step  19

Go to Step  5

5

  1. Turn OFF the ignition.
  2. Attempt to rotate the negative battery cable connector clockwise with light finger pressure.

Does the negative connector rotate?

--

Go to Step  6

Go to Step  7

6

Use a torque wrench to loosen the negative battery terminal bolt in order to verify the torque.

Is the torque above the specified value?

10 N·m

Go to Step  8

Go to Step  7

7

Caution: Refer to Battery Disconnect Caution in the Preface section.

Disconnect the negative battery cable.

Is the cable disconnected?

--

Go to Step  9

--

8

Caution: Refer to Battery Disconnect Caution in the Preface section.

Disconnect the negative battery cable.

Inspect for the following conditions and repair as needed:

    • The cable bolt is too long or is damaged at the end.
    • There is foreign material present inside the nut in the battery terminal.
    • Damage to the battery terminal face or cable connector ring.

Is the repair complete?

--

Go to Step  9

--

9

Rotate the positive battery cable connector clockwise with light finger pressure.

Does the positive connector rotate?

--

Go to Step  10

Go to Step  11

10

Use a torque wrench in order to verify the torque to loosen the positive battery terminal bolt.

Is the torque above the specified value?

10 N·m

Go to Step  12

Go to Step  11

11

Caution: Refer to Battery Disconnect Caution in the Preface section.

Disconnect the positive battery cable.

Is the cable disconnected?

--

Go to Step  13

--

12

Caution: Refer to Battery Disconnect Caution in the Preface section.

  1. Disconnect the negative battery cable.
  2. Inspect for the following conditions and repair as needed:
  3. • The cable bolt is too long or is damaged at the end.
    • There is foreign material present inside the nut in the battery terminal.
    • Damage to the battery terminal face or cable connector ring.

Is the repair complete?

--

Go to Step  13

--

13

  1. Clean and wire brush the lead face of both battery terminals and the metal contact rings in both cable connectors.
  2. Remove the bolts from the cable connectors in order to provide access to the connector rings as needed.
  3. If either the battery terminals or the cable rings are excessively damaged or corroded, replace as needed.

Are the metal connecting parts clean and in good condition?

--

Go to Step  14

--

14

  1. Connect the positive battery cable to the battery positive terminal.
  2. Tighten the cable bolt to the specified value.

Is the cable bolt correctly tightened?

--

Go to Step  15

--

15

  1. Connect the negative battery cable to the battery negative terminal.
  2. Tighten the cable bolt to the specified value.

Is the cable bolt correctly tightened?

--

Go to Step  16

--

16

Important: Ensure all electrical loads are turned OFF.

  1. Install the J 42000 .
  2. Follow the tester's directions.
  3. Follow any direction from the tester.

Did the tester pass the battery?

--

Go to Step  17

Go to Step  18

17

  1. Press the CODE button on the J 42000 .
  2. Write the displayed code on the repair order for any warranty purposes.

Did you complete this action?

--

Battery OK

--

18

  1. Press the CODE button on the J 42000 .
  2. Write the displayed code on the repair order for any warranty purposes.

Replace the battery. Refer to Battery Replacement .

Did you complete the replacement?

--

Battery OK

--

19

Replace the battery. Refer to Battery Replacement .

Did you complete the replacement?

--

Battery OK

--