Diagnostic Aids

WARNING: This page is about a different car, the 2003 GMC Sonoma, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Refer to BATTERY DISCONNECT CAUTION in Cautions and Notices.

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.

Fig 1: Battery Inspection/Test Chart (1 Of 3)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Battery Inspection/Test Chart (2 Of 3)

Courtesy of GENERAL MOTORS CORP.

Fig 3: Battery Inspection/Test Chart (3 Of 3)

Courtesy of GENERAL MOTORS CORP.