Mercedes-Benz Sprinter / Dodge Sprinter. Manual - part 207

stalled equipment on this model. Some vehicles are
equipped with a second auxiliary battery for running
additional electrical equipment. The standard battery
is located in the engine compartment, while the aux-
iliary battery (if equipped) is located under the pas-
sengers front seat. The battery system for this
vehicle covers the following related components,
which are covered in further detail later in this sec-
tion of the service manual:

• Battery - The 12v storage battery(s) provides a

reliable means of storing a renewable source of elec-
trical energy within the vehicle.

• Battery Cables - The battery cables connect

the battery terminal posts to the vehicle electrical
system.

• Battery Holddown - The battery holddown

hardware secures the battery in the battery tray in
the engine compartment.

• Battery Tray - The battery tray provides a

secure mounting location in the vehicle for the bat-
tery and an anchor point for the battery holddown
hardware.

ENGINE SYSTEMS

8F - 1

For battery system maintenance schedules and

jump starting procedures, see the owner’s manual in
the vehicle glove box. Optionally, refer to the Lubri-
cation and Maintenance section of this manual for
the recommended battery maintenance schedules and
for the proper battery jump starting procedure. While
battery charging can be considered a maintenance
procedure,

the

battery

charging

procedure

and

related information are located later in this section of
this service manual. This was done because the bat-
tery must be fully-charged before any battery system
diagnosis or testing procedures can be performed.

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 acces-
sory 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 sys-
tem 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 abnormal 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 complete 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 thor-
oughly tested and inspected any time a battery needs
to be charged or replaced. The cause of abnormal bat-
tery 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 service information for these systems has been
separated within this service manual to make it eas-
ier to locate the specific information you are seeking.
However, when attempting to diagnose any of these
systems, it is important that you keep their interde-
pendency in mind.

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/ohmme-
ter, 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 Trou-
ble Code (DTC). The PCM will store a DTC in elec-
tronic memory for any failure it detects. Refer to
Charging System for the proper charging system on-
board diagnostic test procedures.

MICRO 420 BATTERY TESTER

The

Micro

420

automotive

battery

tester

designed to help the dealership technicians diagnose
the cause of a defective battery. Follow the instruc-
tion manual supplied with the tester to properly
diagnose a vehicle. If the instruction manual is not
available refer to the standard procedure in this sec-
tion, which includes the directions for using the
Micro 420 battery tester.

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 igni-
tion-off draw is excessive.

1. Refer to the IGNITION-OFF DRAW TEST
Standard Procedure for the proper test proce-
dures. Repair the excessive ignition-off draw, as
required.

2. The charging system is
faulty.

2. Determine if the charging system is perform-
ing 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 Stan-
dard Procedures in this section for additional
test procedures. Charge the faulty battery, as
required.

4. The battery terminal con-
nections are loose or cor-
roded.

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 incor-
rect size or rating for this
vehicle.

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

6. The battery is faulty.

6. Determine the battery cranking capacity using
the Micro 420 battery tester. Refer to the Stan-
dard 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 dam-
aged 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 incor-
rect size or rating for this
vehicle.

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

2. The battery terminal con-
nections are loose or cor-
roded.

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

3. The electrical system igni-
tion-off draw is excessive.

3. Refer to the IGNITION-OFF DRAW TEST
Standard Procedure for the proper test proce-
dures. Repair the faulty electrical system, as re-
quired.

4. The battery is faulty.

4. Test the battery using the Micro 420 battery
tester. Refer to Standard Procedures for addi-
tional test procedures. Replace the faulty bat-
tery, 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 perform-
ing 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 electri-
cal 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 abnor-

mal battery discharging:

1. A faulty or incorrect charging system compo-

nent. Refer to Charging System for additional charg-
ing system diagnosis and testing procedures.

2. A faulty or incorrect battery. Use Micro 420 bat-

tery 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 sys-
tem 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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