Micro 420 Electrical System Tester
The Micro 420 automotive battery system tester is designed to help diagnose the cause of a defective battery. (Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE - USING MICRO 420 BATTERY TESTER) for directions on using the Micro 420 battery tester.
| BATTERY SYSTEM DIAGNOSIS | ||
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| CONDITION | POSSIBLE CAUSES | CORRECTION |
| THE BATTERY SEEMS WEAK OR DEAD WHEN ATTEMPTING TO START THE ENGINE. |
1. The electrical system ignition-off draw is excessive. |
1. (Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE - IGNITION-OFF DRAW TEST) for the proper test procedures. Repair the excessive ignition-off draw, as required. |
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2. The charging system is inoperative. |
2. Determine if the charging system is performing to specifications, (Refer to ELECTRICAL/CHARGING - DIAGNOSIS AND TESTING) . Repair the inoperative charging system, as required. |
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3. The battery is discharged. |
3. Determine the battery state-of-charge using the Micro 420 battery tester, (Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE - USING MICRO 420 BATTERY TESTER) . Charge the battery as required. |
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4. The battery terminal connections are loose or corroded. |
4. (Refer to ELECTRICAL/BATTERY SYSTEM/CABLES - DIAGNOSIS AND TESTING) . Clean and tighten the battery terminal connections, as required. |
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5. The battery has an incorrect size or rating for this vehicle. |
5. (Refer to ELECTRICAL/BATTERY SYSTEM - SPECIFICATIONS) for the proper size and rating. Replace an incorrect battery, as required. |
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6. The battery is inoperative. |
6. Determine the battery cranking capacity using the Micro 420 battery tester, (Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE - USING MICRO 420 BATTERY TESTER) . Replace the inoperative battery, as required. |
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7. The starting system is inoperative. |
7. Determine if the starting system is performing to specifications, (Refer to ELECTRICAL/STARTING - DIAGNOSIS AND TESTING) . Repair the inoperative starting system, as required. |
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8. The battery is physically damaged. |
8. Inspect the battery for loose terminal posts or a cracked and leaking case. Replace the damaged battery, as required. |
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| THE BATTERY STATE OF CHARGE CANNOT BE MAINTAINED. |
1. The battery has an incorrect size or rating for this vehicle. |
1. (Refer to ELECTRICAL/BATTERY SYSTEM - SPECIFICATIONS) for the proper size and rating. Replace an incorrect battery, as required. |
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2. The battery terminal connections are loose or corroded. |
2. (Refer to ELECTRICAL/BATTERY SYSTEM/CABLES - DIAGNOSIS AND TESTING) . Clean and tighten the battery terminal connections, as required. |
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3. The electrical system ignition-off draw is excessive. |
3. (Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE - IGNITION-OFF DRAW TEST) for the proper test procedures. Repair the inoperative electrical system, as required. |
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4. The battery is inoperative. |
4. Test the battery using the Micro 420 battery tester, (Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE - USING MICRO 420 BATTERY TESTER) . Replace the inoperative battery, as required. |
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5. The starting system is inoperative. |
5. Determine if the starting system is performing to specifications, (Refer to ELECTRICAL/STARTING - DIAGNOSIS AND TESTING) . Repair the inoperative starting system, as required. |
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6. The charging system is inoperative. |
6. Determine if the charging system is performing to specifications, (Refer to ELECTRICAL/CHARGING - DIAGNOSIS AND TESTING) . Repair the inoperative charging system, as required. |
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7. Electrical loads exceed the output of the charging system. |
7. Inspect the vehicle for aftermarket electrical equipment which might cause excessive electrical loads. |
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8. Slow driving or prolonged idling with high-amperage draw systems in use. |
8. Advise the vehicle operator, as required. |
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| THE BATTERY WILL NOT ACCEPT A CHARGE. |
1. The battery is inoperative. |
1. Test the battery using the Micro 420 battery tester, (Refer to ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE - USING MICRO 420 BATTERY TESTER) . Replace the inoperative battery, as required. |