Diagnosis And Testing - Single Battery - 12 Volt System

DIAGNOSIS AND TESTING - BATTERY SYSTEM:  The battery, starting, and charging systems are inter-related and should be tested as a complete system. In order for the engine to start and the battery to maintain its proper charge, all of the components that are used in these systems must perform within specifications. It is important that the battery, starting, and charging systems be thoroughly tested and inspected any time a battery needs to be charged or replaced. The cause of abnormal battery discharge, overcharging or early battery failure must be diagnosed and corrected before a battery is replaced and before a vehicle is returned to service. The Powertrain Control Module (PCM) monitors these systems for faults. If the PCM has a Diagnostic Trouble Code (DTC) stored against any of these systems, the DTC(s) should be diagnosed using the DTC diagnostic test procedure.

PRELIMINARY BATTERY CHECKS:  Verify each of the following before charging and testing the battery.

1. Inspect the battery for any physical damage to the battery or posts.
   • If physical damage is obvious, replace the battery and retest.
2. Verify the battery is the proper size and rating for the vehicle. Refer to: BATTERY SPECIFICATIONS .
   • If the battery does not meet the required specifications, replace the battery and retest.
3. Verify the battery and cable connections are tight and clean. Check the battery cable connections at the battery posts, alternator terminal and ground locations.
   • Clean and repair any poor connections and retest.
4. Verify the charging system is operating properly.
   • If the charging system output is low, repair the inoperative charging system.
     NOTE:

     On vehicles that are equipped with the PHEV system, the 12 volt system is charged from the DC/DC converter incorporated in the Integrated Dual Charging Module (IDCM).

5. If the vehicle has a no crank condition but the electrical system has power check the starting system operation.
   • Repair the inoperative starting system as required.
6. Check the battery electrolyte level if applicable. Always use the necessary safety precautions when working with batteries to prevent possible serious or fatal injury.
   • If the electrolyte level is low, fill to the proper level and retest.
7. If the battery, starting and charging systems test good, but the battery discharges after sitting for a short period, check the electrical system for an ignition off draw.

If all preliminary checks are good, test the battery using the GR8 Battery Tester.

CHARGING AND TESTING BATTERIES WITH THE GR8 BATTERY TESTER:  Always use the Midtronics GR8 Instruction Manual that was supplied with the tester as a reference. If the Instruction Manual is not available the following procedure can be used:

1. Disconnect the main battery positive and negative cables to isolate the battery. Connect the special tool # GR8-1220 KIT-CHRY (AGM Battery Tester/Charger Station) directly to the battery posts and perform the battery testing procedure.
2. Using the ARROW key, select out  of vehicle testing and press ENTER to make a selection.
3. If not selected, choose the Cold Cranking Amp (CCA) battery rating. Or select the appropriate battery rating for your area (read menu). The tester will then run its self programmed test of the battery and display the results. Refer to the test result table noted below.
4. While viewing the battery test result, press the CODE button and the tester will prompt you for the last 4 digits of the Vehicle Identification Number (VIN). Use the UP/DOWN arrow buttons to scroll to the correct character; then press ENTER to select and move to the next digit. Then press the ENTER button to view the SERVICE CODE. Pressing the CODE button a second time will return you to the test results.
   1. If the battery fails the load testing below, record the failure code and replace the battery.
   2. If the battery DOES NOT fail the load testing below, reconnect the battery and retest the system. If the battery, starting and charging systems test good, but the battery discharges after sitting, check the electrical system for an ignition off draw.