Battery Inspection/Test
Diagnostic Instructions
Diagnostic Aids
Warning: Refer to Battery Disconnect Warning in the Preface section.
Note:
| • | The battery test using the EL 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 EL 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. |
| | Note: 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 EL 42000 or GM P/N 12303040 terminal adapters. If the adapters that are provided with the EL 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. |
Reference Information
Schematic Reference
Starting and Charging Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Starting System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Special Tools
EL 42000 Battery Tester
For equivalent regional tools, refer to Special Tools .
Circuit/System Testing
Warning: 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.
For Vehicles equipped with OnStar® (UE1) with Back Up Battery:
The Back Up Battery is a redundant power supply to allow limited OnStar® functionality in the event of a main vehicle battery power disruption to the VCIM (OnStar®module). Do not disconnect the main vehicle battery or remove the OnStar® fuse with the ignition key in any position other than OFF. Retained accessory power (RAP) should be allowed to time out or be disabled (simply opening the driver door should disable RAP) before disconnecting power. Disconnecting power to the OnStar® module in any way while the ignition is On or with RAP activated may cause activation of the OnStar® Back-Up Battery (BUB) system and will discharge and permanently damage the back-up battery. Once the Back-Up Battery is activated it will stay on until it has completely discharged. The BUB is not rechargeable and once activated the BUB must be replaced.
- Inspect the C1 Battery for a cracked, broken or damaged case, which may be indicated by battery acid leakage.
| ⇒ | If there is any apparent damage, replace the C1 Battery. |
- Verify the cold cranking amperage and amperage hour rating of the battery to the original battery or original equipment specification.
| ⇒ | If the C1 Battery does not meet or exceed specifications, replace the C1 Battery. |
- Verify that the battery cables are clean and tight. The battery terminal bolts should be torqued as specified in Fastener Tightening Specifications .
| ⇒ | If the battery cables need to be cleaned, clean as required and tighten as specified. |
| ⇒ | If the battery cables are damaged, replace then tighten as specified. |
- Install the EL 42000 and follow directions supplied by the tester.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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