Dodge Durango (HB). Manual - part 251

This vehicle is equipped with a single 12-volt battery. All of the components of the battery system are located within
the engine compartment of the vehicle. The battery system for this vehicle covers the following related components:

•

Battery - A 12 volt storage battery provides a reliable means of storing a renewable source of electrical
energy within the vehicle.

•

Battery Cables - The battery cables connect the battery terminal posts to the vehicle electrical system.

•

Battery Hold down - The battery hold down hardware secures the battery in the battery tray.

•

Battery Tray - The battery tray provides a secure mounting location in the vehicle for the battery and an
anchor point for the battery hold down hardware.

For battery jump starting procedures, refer to Lubrication and Maintenance.

ENGINE SYSTEMS

8F - 1

OPERATION

The battery system is designed to provide a safe, efficient, reliable and mobile means of delivering and storing
electrical energy. This electrical energy is required to operate the engine starting system, as well as to operate
many of the other vehicle accessory systems for limited durations while the engine and/or the charging system are
not operating. The battery system is also designed to provide a reserve of electrical energy to supplement the
charging system for short durations while the engine is running and the electrical current demands of the vehicle
exceed the output of the charging system. In addition to delivering, and storing electrical energy for the vehicle, the
battery system serves as a capacitor and voltage stabilizer for the vehicle electrical system. It absorbs most abnor-
mal or transient voltages caused by the switching of any of the electrical components or circuits in the vehicle.

DIAGNOSIS AND TESTING

BATTERY SYSTEM

The battery, starting, and charging systems in the vehicle operate with one another and must be tested as a com-
plete system. In order for the engine to start and the battery to maintain its charge properly, 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 diagnostic procedures used for the battery, starting, and charging systems include the most basic conventional
diagnostic methods, to the more sophisticated On-Board Diagnostics (OBD) built into the Powertrain Control Module
(PCM). Use of an induction-type milliampere ammeter, a volt/ohmmeter, a battery charger, a carbon pile rheostat
(load tester) and a 12-volt test lamp may be required. All OBD-sensed systems are monitored by the PCM. Each
monitored circuit is assigned a Diagnostic Trouble Code (DTC). The PCM will store a DTC in electronic memory for
any failure it detects.

MICRO 420 BATTERY TESTER

The Micro 420 automotive battery tester is designed to assist the technician diagnose a inoperative battery. Follow
the instruction manual supplied with the tester to properly diagnose a battery. If the instruction manual is not avail-
able, (Refer to 8 - ELECTRICAL/BATTERY SYSTEM/BATTERY - STANDARD PROCEDURE).

8F - 2

BATTERY SYSTEM

BATTERY SYSTEM DIAGNOSIS

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 the IGNITION-OFF DRAW TEST
Standard Procedure for the proper test
procedures. Repair the excessive ignition-off
draw, as required.

2. The charging system is
faulty.

2. Determine if the charging system is performing
to specifications. Refer to Charging System for
additional charging system diagnosis and testing
procedures. Repair the faulty charging system, as
required.

3. The battery is discharged.

3. Determine the battery state-of-charge using the
Micro 420 battery tester. Refer to the Standard
Procedures in this section for additional test
procedures. Charge the faulty battery, as
required.

4. The battery terminal
connections are loose or
corroded.

4. Refer to Battery Cables for the proper battery
cable diagnosis and testing procedures. Clean
and tighten the battery terminal connections, as
required.

5. The battery has an
incorrect size or rating for
this vehicle.

5. Refer to Battery System Specifications for the
proper size and rating. Replace an incorrect
battery, as required.

6. The battery is faulty.

6. Determine the battery cranking capacity using
the Micro 420 battery tester. Refer to the
Standard Procedures in this section for additional
test procedures. Replace the faulty battery, as
required.

7. The starting system is
faulty.

7. Determine if the starting system is performing
to specifications. Refer to Starting System for the
proper starting system diagnosis and testing
procedures. Repair the faulty starting system, as
required.

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.

BATTERY SYSTEM

8F - 3

BATTERY SYSTEM DIAGNOSIS

CONDITION

POSSIBLE CAUSES

CORRECTION

THE BATTERY STATE OF
CHARGE CANNOT BE
MAINTAINED.

1. The battery has an
incorrect size or rating for
this vehicle.

1. Refer to Battery System Specifications for the
proper specifications. Replace an incorrect
battery, as required.

2. The battery terminal
connections are loose or
corroded.

2. Refer to Battery Cable for the proper cable
diagnosis and testing procedures. Clean and
tighten the battery terminal connections, as
required.

3. The electrical system
ignition-off draw is excessive.

3. Refer to the IGNITION-OFF DRAW TEST
Standard Procedure for the proper test
procedures. Repair the faulty electrical system, as
required.

4. The battery is faulty.

4. Test the battery using the Micro 420 battery
tester. Refer to Standard Procedures for
additional test procedures. Replace the faulty
battery, as required.

5. The starting system is
faulty.

5. Determine if the starting system is performing
to specifications. Refer to Starting System for the
proper starting system diagnosis and testing
procedures. Repair the faulty starting system, as
required.

6. The charging system is
faulty.

6. Determine if the charging system is performing
to specifications. Refer to Charging System for
additional charging system diagnosis and testing
procedures. Repair the faulty charging system, as
required.

7. Electrical loads exceed the
output of the charging
system.

7. Inspect the vehicle for aftermarket electrical
equipment which might cause excessive electrical
loads.

8. Slow driving or prolonged
idling with high-amperage
draw systems in use.

8. Advise the vehicle operator, as required.

THE BATTERY WILL NOT
ACCEPT A CHARGE.

1. The battery is faulty.

1. Test the battery using the Micro 420 battery
tester. Charge or replace the faulty battery, as
required.

ABNORMAL BATTERY DISCHARGING

Any of the following conditions can result in abnormal battery discharging:

1. A faulty or incorrect charging system component. Refer to Charging System for additional charging system
diagnosis and testing procedures.

2. A faulty or incorrect battery. Use Micro 420 battery tester and refer to Battery System for additional battery
diagnosis and testing procedures.

3. A faulty circuit or component causing excessive ignition-off draw.

4. Electrical loads that exceed the output of the charging system. This can be due to equipment installed after
manufacture, or repeated short trip use.

5. A faulty or incorrect starting system component. Refer to Starting System for the proper starting system
diagnosis and testing procedures.

6. Corroded or loose battery posts and/or terminal clamps.

7. Slow driving speeds (heavy traffic conditions) or prolonged idling, with high-amperage draw systems in use.

8F - 4

BATTERY SYSTEM

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