GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Impala 🢒 Preface 🢒 Cautions and Notices 🢒 Battery Inspection/Test

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Special Tools

J 42000 Battery Tester

Diagnostic Aids

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

Important: 

   • The battery test using the J 42000 Battery Tester 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.
   • Use the Out of Vehicle test for each battery when testing a vehicle with dual batteries.

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 or BAD CELL-REPLACE 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.

        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. Use the test code from the second, or Out of Vehicle test.

        4. Follow the instructions for testing a removed battery.
        5. Replace the battery only if the second test shows a REPLACE BATTERY or BAD CELL-REPLACE 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 GM P/N 12303040 terminal adapters. If the adapters that are provided with the J 42000 require replacement, use GM 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.

Circuit/System Testing

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Inspect the battery for a cracked, broken, or damaged case, which may be indicated by battery acid leakage.
    2. ⇒If there is any apparent damage, replace the battery.
  2. Verify the cold cranking amperage (CCA), and reserve capacity (RC) and/or amp hour (AH) rating of the battery to the original battery or original equipment (OE) specification. Refer to Battery Usage .
    3. ⇒If the battery does not meet or exceed specifications, replace the battery.
  3. Verify that the battery cables are clean and tight. The battery terminal bolts should be torqued as specified in Fastener Tightening Specifications .
    4. ⇒If the battery cable(s) need to be cleaned, clean as required and tighten as specified.
    ⇒If the battery cable(s) are damaged, replace then tighten as specified.
  4. Install the J 42000 and follow directions supplied by the tester.
    5. ⇒If the tester calls for charging the battery, refer to Battery Charging .

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Battery Positive and Negative Cable Replacement
    •  Battery Replacement