volt CHRYSLER VOYAGER 2004 Owner's Manual

NOTE: PCM Inputs:
²Air Conditioning Pressure Transducer
²Ambient temperature Sensor
²ASD Relay
²Battery Temperature Sensor (NGC)
²Battery Voltage
²Brake Switch
²Camshaft Position Sensor
²Crankshaft Position Sensor
²Distance Sensor (from transmission control mod-
ule)
²EGR Position Feedback
²Engine Coolant Temperature Sensor
²Heated Oxygen Sensors
²Ignition sense
²Intake Air Temperature Sensor
²Knock Sensor
²Leak Detection Pump Feedback
²Manifold Absolute Pressure (MAP) Sensor
²Park/Neutral
²PCI Bus
²Power Steering Pressure Switch
²Proportional Purge Sense
²SCI Receive
²Speed Control
²Throttle Position Sensor
²Torque Management Input
²Transaxle Control Module (3.3/3.8L Only)
²Transmission Control Relay (Switched B+) (2.4L
Only)
²Transmission Pressure Switches (2.4L Only)
²Transmission Temperature Sensor (2.4L Only)
²Transmission Input Shaft Speed Sensor (2.4L
Only)
²Transmission Output Shaft Speed Sensor (2.4L
Only)
²Transaxle Gear Engagement
²Vehicle Speed
NOTE: PCM Outputs:
²Air Conditioning Clutch Relay
²Automatic Shut Down (ASD) and Fuel Pump
Relays
²Data Link Connector (PCI and SCI Transmit)
²Double Start Override
²EGR Solenoid
²Fuel Injectors
²Generator Field
²High Speed Fan Relay
²Idle Air Control Motor
²Ignition Coils
²Leak Detection Pump
²Low Speed Fan Relay
²MTV Actuator
²Proportional Purge Solenoid²SRV Valve
²Speed Control Relay
²Speed Control Vent Relay
²Speed Control Vacuum Relay
²8 Volt Output
²5 Volt Output
²Torque Reduction Request
²Transmission Control Relay (2.4L Only)
²Transmission Solenoids (2.4L Only)
²Vehicle Speed
Based on inputs it receives, the powertrain control
module (PCM) adjusts fuel injector pulse width, idle
speed, ignition timing, and canister purge operation.
The PCM regulates the cooling fans, air conditioning
and speed control systems. The PCM changes gener-
ator charge rate by adjusting the generator field.
The PCM adjusts injector pulse width (air-fuel
ratio) based on the following inputs.
²Battery Voltage
²Intake Air Temperature Sensor
²Engine Coolant Temperature
²Engine Speed (crankshaft position sensor)
²Exhaust Gas Oxygen Content (heated oxygen
sensors)
²Manifold Absolute Pressure
²Throttle Position
The PCM adjusts engine idle speed through the
idle air control motor based on the following inputs.
²Brake Switch
²Engine Coolant Temperature
²Engine Speed (crankshaft position sensor)
²Park/Neutral
²Transaxle Gear Engagement
²Throttle Position
²Vehicle Speed
The PCM adjusts ignition timing based on the fol-
lowing inputs.
²Intake Air Temperature
²Engine Coolant Temperature
²Engine Speed (crankshaft position sensor)
²Knock Sensor
²Manifold Absolute Pressure
²Park/Neutral
²Transaxle Gear Engagement
²Throttle Position
The automatic shut down (ASD) and fuel pump
relays are mounted externally, but turned on and off
by the powertrain control module through the same
circuit.
The camshaft and crankshaft signals are sent to
the powertrain control module. If the PCM does not
receive both signals within approximately one second
of engine cranking, it deactivates the ASD and fuel
pump relays. When these relays are deactivated,
power is shut off to the fuel injectors, ignition coils,
8E - 12 ELECTRONIC CONTROL MODULESRS
POWERTRAIN CONTROL MODULE (Continued)

fuel pump and the heating element in each oxygen
sensor.
The PCM contains a voltage converter that
changes battery voltage to a regulated 8.0 volts. The
8.0 volts power the camshaft position sensor, crank-
shaft position sensor and vehicle speed sensor. The
PCM also provides a 5.0 volts supply for the engine
coolant temperature sensor, intake air temperature
sensor, manifold absolute pressure sensor and throt-
tle position sensor.
The PCM engine control strategy prevents reduced
idle speeds until after the engine operates for 320 km
(200 miles). If the PCM is replaced after 320 km (200
miles) of usage, update the mileage in new PCM. Use
the DRBIIItscan tool to change the mileage in the
PCM. Refer to the appropriate Powertrain Diagnostic
Manual and the DRBIIItscan tool.
TRANSMISSION CONTROL (2.4L MODELS ONLY)
CLUTCH VOLUME INDEX (CVI)
An important function of the PCM is to monitor
Clutch Volume Index (CVI). CVIs represent the vol-
ume of fluid needed to compress a clutch pack.
The PCM monitors gear ratio changes by monitor-
ing the Input and Output Speed Sensors. The Input,
or Turbine Speed Sensor sends an electrical signal to
the PCM that represents input shaft rpm. The Out-
put Speed Sensor provides the PCM with output
shaft speed information.
By comparing the two inputs, the PCM can deter-
mine transaxle gear ratio. This is important to the
CVI calculation because the PCM determines CVIs
by monitoring how long it takes for a gear change to
occur (Fig. 10).
Gear ratios can be determined by using the DRB
Scan Tool and reading the Input/Output Speed Sen-
sor values in the ªMonitorsº display. Gear ratio can
be obtained by dividing the Input Speed Sensor value
by the Output Speed Sensor value.
For example, if the input shaft is rotating at 1000
rpm and the output shaft is rotating at 500 rpm,
then the PCM can determine that the gear ratio is
2:1. In direct drive (3rd gear), the gear ratio changesto 1:1. The gear ratio changes as clutches are applied
and released. By monitoring the length of time it
takes for the gear ratio to change following a shift
request, the PCM can determine the volume of fluid
used to apply or release a friction element.
The volume of transmission fluid needed to apply
the friction elements are continuously updated for
adaptive controls. As friction material wears, the vol-
ume of fluid need to apply the element increases.
Certain mechanical problems within the clutch
assemblies (broken return springs, out of position
snap rings, excessive clutch pack clearance, improper
assembly, etc.) can cause inadequate or out-of-range
clutch volumes. Also, defective Input/Output Speed
Sensors and wiring can cause these conditions. The
following chart identifies the appropriate clutch vol-
umes and when they are monitored/updated:
CLUTCH VOLUMES
ClutchWhen Updated
Proper Clutch
Volume
Shift Sequence Oil Temperature Throttle Angle
L/R2-1 or 3-1 coast
downshift>70É <5É 35to83
2/4 1-2 shift
> 110É5 - 54É20 to 77
OD 2-3 shift 48 to 150
UD 4-3 or 4-2 shift > 5É 24 to 70
Fig. 10 Example of CVI Calculation
1 - OUTPUT SPEED SENSOR
2 - OUTPUT SHAFT
3 - CLUTCH PACK
4 - SEPARATOR PLATE
5 - FRICTION DISCS
6 - INPUT SHAFT
7 - INPUT SPEED SENSOR
8 - PISTON AND SEAL
RSELECTRONIC CONTROL MODULES8E-13
POWERTRAIN CONTROL MODULE (Continued)

OPERATION - SENSOR RETURN - PCM INPUT
The sensor return circuit provides a low electrical
noise ground reference for all of the systems sensors.
The sensor return circuit connects to internal ground
circuits within the Powertrain Control Module
(PCM).
OPERATION - DATA BUS COMMUNICATION
RECEIVE - PCM INPUT
The PCM uses the SCI communication bus to pre-
form engine diagnostics and flash operations. The
transmission side of the PCM uses the SCI commu-
nication bus to flash new software. However, diagnos-
tics is performed via the vehicles J1850 bus for the
transmission side of the PCM.
OPERATION - IGNITION SENSE - PCM INPUT
The ignition sense input informs the Powertrain
Control Module (PCM) that the ignition switch is in
the crank or run position.
OPERATION - PCM GROUND
Ground is provided through multiple pins of the
PCM connector. Depending on the vehicle there may
be as many as two different ground pins. There are
power grounds and sensor grounds.
The power grounds are used to control the ground
side relays, solenoids, ignition coil or injectors. The
signal ground is used for any input that uses sensor
return for ground, and the ground side of any inter-
nal processing component.
The PCM case is shielded to prevent RFI and EMI.
The PCM case is grounded and must be firmly
attached to a good, clean body ground.
Internally all grounds are connected together, how-
ever there is noise suppression on the sensor ground.
For EMI and RFI protection the housing and cover
are also grounded separately from the ground pins.
OPERATION
OPERATION - 8-VOLT SUPPLY - PCM OUTPUT
- SBEC CONTROLLER
The PCM supplies 8 volts to the crankshaft posi-
tion sensor, camshaft position sensor.
OPERATION - 5 VOLT SUPPLY - PCM OUTPUT
The PCM supplies 5 volts to the following sensors:
²A/C pressure transducer
²Ambient Temperature sensor
²Battery temperature
²Camshaft Position Sensor (NGC)
²Crankshaft Position Sensor (NGC)
²Electronic Throttle Control (1.6L)²Engine coolant temperature sensor
²Inlet Air Temperature Sensor
²Knock sensor
²Linear EGR solenoid (if equipped)
²Manifold absolute pressure sensor
²Oil Pressure Switch
²Pedal Position Sensor (1.6L)
²Throttle position sensor
²Vehicle Speed Sensor
STANDARD PROCEDURE
STANDARD PROCEDURE - OBTAINING
DIAGNOSTIC TROUBLE CODES
BULB CHECK
Key on: Bulb illuminated until vehicle starts, as
long as all once per trip (readiness) monitors com-
pleted. If monitors havenotbeen completed, then:
Key on: bulb check for about 5 to 8 seconds, lamp
then flashes if once per trip (readiness) monitors
havenotbeen completed until vehicle is started,
then MIL is extinguished.
OBTAINING DTC'S USING DRB SCAN TOOL
(1) Connect the DRB scan tool to the data link
(diagnostic) connector. This connector is located in
the passenger compartment; at the lower edge of
instrument panel; near the steering column.
(2) Turn the ignition switch on and access the
ªRead Faultº screen.
(3) Record all the DTC's and ªfreeze frameº infor-
mation shown on the DRB scan tool.
(4) To erase DTC's, use the ªErase Trouble Codeº
data screen on the DRB scan tool.Do not erase any
DTC's until problems have been investigated
and repairs have been performed.
STANDARD PROCEDURE - PINION FACTOR
SETTING
NOTE: This procedure must be performed if the
PCM/TCM has been replaced with a NEW or
replacement unit. Failure to perform this procedure
will result in an inoperative or improperly calibrated
speedometer.
The vehicle speed readings for the speedometer are
taken from the output speed sensor. The PCM/TCM
must be calibrated to the different combinations of
equipment (final drive and tires) available. Pinion
Factor allows the technician to set the Powertrain/
Transmission Control Module initial setting so that
the speedometer readings will be correct. To properly
RSELECTRONIC CONTROL MODULES8E-15
POWERTRAIN CONTROL MODULE (Continued)

(2) Remove the appropriate door trim panel from
the vehicle. Refer to Body for the procedure.
(3) Remove the weather shield. Refer to Body for
the procedure.
(4) Disconnect the power door control module elec-
trical connectors. Slide the red locking tab out (away
from module) and depress connector retaining tab,
while pulling straight apart.
(5) Remove the control module retaining screw
(Fig. 15).
(6) Remove the module from the vehicle.
INSTALLATION
(1) Position the control module and install the
retaining screw.
(2) Connect the control module electrical connec-
tors. Slide the locking tab into the locked position.
(3) Install the appropriate door trim panel on the
vehicle. Refer to Body for the procedure.
(4) Install the weather shield. Refer to Body for
the procedure.
(5) Connect the negative battery cable.
(6) Using an appropriate scan tool, check and
erase any power door control module diagnostic trou-
ble codes.
(7) Verify power door system operation. Cycle the
power door through one complete open and close
cycle.
TRANSMISSION CONTROL
MODULE
DESCRIPTION
On models equipped with the 2.4L Engine option,
the Transmission Control Module (TCM) is located
behind the left fender and is fastened with three
screws to three clips in the left frame rail forward of
the suspension (Fig. 16). Models equipped with the
3.3/3.8L Engine option utilize a Powertrain Control
Module (PCM) which incorporates TCM functionality.
OPERATION
The TCM is the controlling unit for all electronic
operations of the transaxle. The TCM receives infor-
mation regarding vehicle operation from both direct
and indirect inputs, and selects the operational mode
of the transaxle. Direct inputs are hardwired to, and
used specifically by the TCM. Indirect inputs origi-
nate from other components/modules, and are shared
with the TCM via the J1850 communication bus.
Some examples ofdirect inputsto the TCM are:
²Battery (B+) voltage
²Ignition ªONº voltage
²Transmission Control Relay (Switched B+)
²Throttle Position Sensor²Crankshaft Position Sensor (CKP)
²Transmission Range Sensor (TRS)
²Pressure Switches (L/R, 2/4, OD)
²Transmission Temperature Sensor (Integral to
TRS)
²Input Shaft Speed Sensor
²Output Shaft Speed Sensor
Some examples ofindirect inputsto the TCM
are:
²Engine/Body Identification
²Manifold Pressure
²Target Idle
²Torque Reduction Confirmation
²Speed Control ON/OFF Switch
²Engine Coolant Temperature
²Ambient/Battery Temperature
²Brake Switch Status
²DRB Communication
Based on the information received from these var-
ious inputs, the TCM determines the appropriate
shift schedule and shift points, depending on the
present operating conditions and driver demand.
This is possible through the control of various direct
and indirect outputs.
Some examples of TCMdirect outputsare:
²Transmission Control Relay
²Solenoids (LR/CC, 2/4, OD and UD)
²Vehicle Speed (to PCM)
²Torque Reduction Request (to PCM)
An example of a TCMindirect outputis:
²Transmission Temperature (to PCM)
Fig. 16 Transmission Control Module (TCM)
Location
1 - TRANSMISSION CONTROL MODULE (TCM)
8E - 20 ELECTRONIC CONTROL MODULESRS
SLIDING DOOR CONTROL MODULE (Continued)

ENGINE SYSTEMS
TABLE OF CONTENTS
page page
BATTERY SYSTEM......................... 1
CHARGING.............................. 20STARTING............................... 28
BATTERY SYSTEM
TABLE OF CONTENTS
page page
BATTERY SYSTEM
DESCRIPTION..........................1
OPERATION............................2
DIAGNOSIS AND TESTING - BATTERY
SYSTEM.............................2
CLEANING.............................5
INSPECTION...........................5
SPECIFICATIONS........................6
SPECIAL TOOLS
BATTERY SYSTEM SPECIAL TOOLS.......7
BATTERY
DESCRIPTION..........................7
OPERATION............................9
DIAGNOSIS AND TESTING - BATTERY.......9
STANDARD PROCEDURE
STANDARD PROCEDURE - SPIRAL PLATE
BATTERY CHARGING..................10
STANDARD PROCEDURE -
CONVENTIONAL BATTERY CHARGING.....11
STANDARD PROCEDURE - OPEN-CIRCUIT
VOLTAGE TEST.......................13
STANDARD PROCEDURE - IGNITION-OFF
DRAW TEST.........................13
STANDARD PROCEDURE - CHECKING
BATTERY ELECTROLYTE LEVEL.........14REMOVAL - BATTERY...................15
INSTALLATION.........................15
BATTERY HOLDDOWN
DESCRIPTION.........................15
OPERATION...........................15
REMOVAL.............................16
INSTALLATION.........................16
BATTERY CABLES
DESCRIPTION.........................16
OPERATION...........................16
DIAGNOSIS AND TESTING - BATTERY CABLE . 16
REMOVAL.............................18
INSTALLATION.........................18
BATTERY TRAY
DESCRIPTION.........................18
OPERATION...........................19
REMOVAL.............................19
INSTALLATION.........................19
THERMOWRAP
DESCRIPTION.........................19
OPERATION...........................19
REMOVAL.............................19
INSTALLATION.........................19
BATTERY SYSTEM
DESCRIPTION
A single 12-volt battery is standard factory-in-
stalled equipment on this model. All of the compo-
nents of the battery system are located within the
engine compartment of the vehicle. The battery sys-
tem for this vehicle covers the following related com-ponents, which are covered in further detail later in
this section of the service manual:
²Battery- The storage battery provides a reli-
able means of storing a renewable source of electrical
energy within the vehicle.
²Battery Cable- The battery cables connect the
battery terminal posts to the vehicle electrical sys-
tem.
RSENGINE SYSTEMS8F-1

²Battery Holddown- The battery holddown
hardware secures the battery in the battery tray in
the engine compartment.
²Battery Thermowrap- The battery thermow-
rap insulates the battery to protect it from engine
compartment temperature extremes.
²Battery 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.
For battery system maintenance schedules and
jump starting procedure, 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 system tester is
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 SYSTEMRS
BATTERY SYSTEM (Continued)

(4) Inspect the battery thermowrap for tears,
cracks, deformation or other damage. Replace any
battery thermal guard that has been damaged.
(5) Inspect the battery built-in test indicator sight
glass(if equipped) for an indication of the battery con-
dition. If the battery is discharged, charge as
required. Refer to Standard Procedures for the
proper battery built-in indicator test procedures. Also
refer to Standard Procedures for the proper battery
charging procedures.
SPECIFICATIONS
The battery Group Size number, the Cold Cranking
Amperage (CCA) rating, and the Reserve Capacity
(RC) rating or Ampere-Hours (AH) rating can be
found on the original equipment battery label. Be
certain that a replacement battery has the correct
Group Size number, as well as CCA, and RC or AH
ratings that equal or exceed the original equipment
specification for the vehicle being serviced. Battery
sizes and ratings are discussed in more detail below.
²Group Size- The outside dimensions and ter-
minal placement of the battery conform to standards
established by the Battery Council International
(BCI). Each battery is assigned a BCI Group Size
number to help identify a correctly-sized replace-
ment.
²Cold Cranking Amperage- The Cold Crank-
ing Amperage (CCA) rating specifies how much cur-
rent (in amperes) the battery can deliver for thirty
seconds at -18É C (0É F). Terminal voltage must not
fall below 7.2 volts during or after the thirty second
discharge period. The CCA required is generally
higher as engine displacement increases, depending
also upon the starter current draw requirements.
²Reserve Capacity- The Reserve Capacity (RC)
rating specifies the time (in minutes) it takes for bat-
tery terminal voltage to fall below 10.5 volts, at a
discharge rate of 25 amperes. RC is determined with
the battery fully-charged at 26.7É C (80É F). This rat-
ing estimates how long the battery might last after a
charging system failure, under minimum electrical
load.
²Ampere-Hours- The Ampere-Hours (AH) rat-
ing specifies the current (in amperes) that a battery
can deliver steadily for twenty hours, with the volt-
age in the battery not falling below 10.5 volts. This
rating is also sometimes identified as the twenty-
hour discharge rating.
BATTERY CLASSIFICATIONS & RATINGS
Part NumberBCI Group Size
ClassificationCold Cranking
AmperageReserve
CapacityAmpere -
HoursLoad Test
Amperage
4686158AD 34 500 110 Minutes 60 250
4727159AD 34 600 120 Minutes 66 300
4727242AD DIN H6 600 120 Minutes 66 300
4868999AA 34 700 95 Minutes 50 350
Fig. 3 Clean Battery Terminal Post - Typical
1 - TERMINAL BRUSH
2 - BATTERY CABLE
3 - BATTERY
8F - 6 BATTERY SYSTEMRS
BATTERY SYSTEM (Continued)

SPECIAL TOOLS
BATTERY SYSTEM SPECIAL TOOLS
BATTERY
DESCRIPTION
There are three different batteries available on this
model. Vehicles equipped with a diesel engine utilize
a spiral wound plate designed battery with recombi-
nation technology. This is a maintenance-free battery
that is capable of delivering more power than a con-
ventional battery. This additional power is required
by a diesel engine during cold cranking. Vehicles
equipped with a gasoline engine utilize a conven-
tional battery. Refer to the following information for
detailed differences and descriptions of these batter-
ies.
SPIRAL PLATE BATTERY - DIESEL ENGINE
Spiral plate technology takes the elements of tradi-
tional batteries - lead and sulfuric acid - to the next
level. By tightly winding layers of spiral grids and
acid-permeated vitreous separators into cells, the
manufacturer has developed a battery with more
power and service life than conventional batteries the
same size. The spiral plate battery is completely, per-
manently sealed. Through gas recombination, hydro-
gen and oxygen within the battery are captured
during normal charging and reunited to form the
water within the electrolyte, eliminating the need to
add distilled water. Therefore, these batteries havenon-removable battery vent caps (Fig. 4). Watercan-
notbe added to this battery.
The acid inside a spiral plate battery is bound
within the vitreous separators, ending the threat of
acid leaks. This feature allows the battery to be
installed in any position anywhere in the vehicle.
Spiral plate technology is the process by which the
plates holding the active material in the battery are
wound tightly in coils instead of hanging flat, like
conventional batteries. This design has a lower inter-
nal resistance and also increases the active material
surface area.
WARNING: NEVER EXCEED 14.4 VOLTS WHEN
CHARGING A SPIRAL PLATE BATTERY. PERSONAL
INJURY AND/OR BATTERY DAMAGE MAY RESULT.
Due to the maintanance-free design, distilled water
cannot be added to this battery. Therefore, if more
than 14.4 volts are used during the spiral plate bat-
tery charging process, water vapor can be exhausted
through the pressure-sensitive battery vents and lost
for good. This can permanently damage the spiral
plate battery. Never exceed 14.4 volts when charging
a spiral plate battery. Personal injury and/or battery
damage may result.
CONVENTIONAL BATTERY - GASOLINE ENGINE
Low-maintenance batteriesare used on export
vehicles equipped with a gasoline engine, these bat-
teries have removable battery cell caps (Fig. 5).
Watercanbe added to this battery. Under normal
MICRO 420 BATTERY TESTER
Fig. 4 MAINTENANCE-FREE DIESEL ENGINE
BATTERY
RSBATTERY SYSTEM8F-7
BATTERY SYSTEM (Continued)

found on the original equipment battery label. Be
certain that a replacement battery has the correct
Group Size number, as well as CCA, and RC or AH
ratings that equal or exceed the original equipment
specification for the vehicle being serviced. Refer to
Battery Specificationsin this group for the loca-
tion of the proper factory-installed battery specifica-
tions.
OPERATION
The battery is designed to store electrical energy in
a chemical form. When an electrical load is applied to
the terminals of the battery, an electrochemical reac-
tion occurs. This reaction causes the battery to dis-
charge electrical current from its terminals. As the
battery discharges, a gradual chemical change takes
place within each cell. The sulfuric acid in the elec-
trolyte combines with the plate materials, causing
both plates to slowly change to lead sulfate. At the
same time, oxygen from the positive plate material
combines with hydrogen from the sulfuric acid, caus-
ing the electrolyte to become mainly water. The
chemical changes within the battery are caused by
the movement of excess or free electrons between the
positive and negative plate groups. This movement of
electrons produces a flow of electrical current
through the load device attached to the battery ter-
minals.
As the plate materials become more similar chem-
ically, and the electrolyte becomes less acid, the volt-
age potential of each cell is reduced. However, by
charging the battery with a voltage higher than that
of the battery itself, the battery discharging process
is reversed. Charging the battery gradually changes
the sulfated lead plates back into sponge lead and
lead dioxide, and the water back into sulfuric acid.
This action restores the difference in the electron
charges deposited on the plates, and the voltage
potential of the battery cells. For a battery to remain
useful, it must be able to produce high-amperage cur-
rent over an extended period. A battery must also be
able to accept a charge, so that its voltage potential
may be restored.
The battery is vented to release excess hydrogen
gas that is created when the battery is being charged
or discharged. However, even with these vents,
hydrogen gas can collect in or around the battery. If
hydrogen gas is exposed to flame or sparks, it may
ignite. If the electrolyte level is low, the battery may
arc internally and explode. If the battery is equipped
with removable cell caps, add distilled water when-
ever the electrolyte level is below the top of the
plates. If the battery cell caps cannot be removed, the
battery must be replaced if the electrolyte level
becomes low.
DIAGNOSIS AND TESTING - BATTERY
The battery must be completely charged and the
terminals should be properly cleaned and inspected
before diagnostic procedures are performed. Refer to
Battery System Cleaning for the proper cleaning pro-
cedures, and Battery System Inspection for the
proper battery inspection procedures. Refer to Stan-
dard Procedures for the proper battery charging pro-
cedures.
MICRO 420 BATTERY TESTER
The Micro 420 automotive battery tester is
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.
WARNING: IF THE BATTERY SHOWS SIGNS OF
FREEZING, LEAKING OR LOOSE POSTS, DO NOT
TEST, ASSIST-BOOST, OR CHARGE. THE BATTERY
MAY ARC INTERNALLY AND EXPLODE. PERSONAL
INJURY AND/OR VEHICLE DAMAGE MAY RESULT.
WARNING: EXPLOSIVE HYDROGEN GAS FORMS IN
AND AROUND THE BATTERY. DO NOT SMOKE,
USE FLAME, OR CREATE SPARKS NEAR THE BAT-
TERY. PERSONAL INJURY AND/OR VEHICLE DAM-
AGE MAY RESULT.
WARNING: THE BATTERY CONTAINS SULFURIC
ACID, WHICH IS POISONOUS AND CAUSTIC. AVOID
CONTACT WITH THE SKIN, EYES, OR CLOTHING.
IN THE EVENT OF CONTACT, FLUSH WITH WATER
AND CALL A PHYSICIAN IMMEDIATELY. KEEP OUT
OF THE REACH OF CHILDREN.
A battery that will not accept a charge is faulty,
and must be replaced. Further testing is not
required. A fully-charged battery must be tested to
determine its cranking capacity. A battery that is ful-
ly-charged, but does not pass the Micro 420 or load
test, is faulty and must be replaced.
NOTE: Completely discharged batteries may take
several hours to accept a charge. Refer to Standard
Procedures for the proper battery charging proce-
dures.
RSBATTERY SYSTEM8F-9
BATTERY (Continued)

STANDARD PROCEDURE
STANDARD PROCEDURE - SPIRAL PLATE
BATTERY CHARGING
Vehicles equipped with a diesel engine utilize a
unique spiral plate battery. This battery has a maxi-
mum charging voltage that must not be exceeded in
order to restore the battery to its full potential, fail-
ure to use the following spiral plate battery charging
procedure could result in damage to the battery or
personal injury.
Battery charging is the means by which the bat-
tery can be restored to its full voltage potential. A
battery is fully-charged when:
²Micro 420 battery tester indicates battery is OK.
²Open-circuit voltage of the battery is 12.65 volts
or above.
²Battery passes Load Test multiple times.
WARNING: IF THE BATTERY SHOWS SIGNS OF
FREEZING, LEAKING, LOOSE POSTS OR LOW
ELECTROLYTE LEVEL, DO NOT TEST, ASSIST-
BOOST, OR CHARGE. THE BATTERY MAY ARC
INTERNALLY AND EXPLODE. PERSONAL INJURY
AND/OR VEHICLE DAMAGE MAY RESULT.
CAUTION: Always disconnect and isolate the bat-
tery negative cable before charging a battery.
Charge the battery directly at the battery terminals.
Do not exceed 14.4 volts while charging a battery.
CAUTION: The battery should not be hot to the
touch. If the battery feels hot to the touch, turn off
the charger and let the battery cool before continu-
ing the charging operation. Damage to the battery
may result.
After the battery has been charged to 12.6 volts or
greater, perform a load test to determine the battery
cranking capacity. Refer to Battery Diagnosis and
Testing for the proper battery test procedures. If the
battery will endure a load test, return the battery to
service. If the battery will not pass a load test, it is
faulty and must be replaced.
Clean and inspect the battery hold downs, tray,
terminals, posts, and top before completing battery
service. Refer to Battery System Cleaning for the
proper battery system cleaning procedures, and Bat-
tery System Inspection for the proper battery system
inspection procedures.
CHARGING A COMPLETELY DISCHARGED
BATTERY ± SPIRAL PLATE BATTERY
The following procedure should be used to recharge
a completely discharged battery. Unless this proce-
dure is properly followed, a good battery may be
needlessly replaced.
(1) Measure the voltage at the battery posts with a
voltmeter, accurate to 1/10 (0.10) volt (Fig. 7). Refer
to Battery Removal and Installation for access
instructions. If the reading is below ten volts, the
battery charging current will be low. It could take
several hours before the battery accepts a current
greater than a few milliamperes. Such low current
may not be detectable on the ammeters built into
many battery chargers.
(2) Disconnect and isolate the battery negative
cable. Connect the battery charger leads. Some bat-
tery chargers are equipped with polarity-sensing cir-
cuitry. This circuitry protects the battery charger and
the battery from being damaged if they are improp-
erly connected. If the battery state-of-charge is too
low for the polarity-sensing circuitry to detect, the
battery charger will not operate. This makes it
appear that the battery will not accept charging cur-
rent. See the instructions provided by the manufac-
turer of the battery charger for details on how to
bypass the polarity-sensing circuitry.
(3) Battery chargers vary in the amount of voltage
and current they provide. The amount of time
required for a battery to accept measurable charging
current at various voltages is shown in the Charge
Rate Table. If the charging current is still not mea-
surable at the end of the charging time, the battery
is faulty and must be replaced. If the charging cur-
rent is measurable during the charging time, the bat-
tery may be good and the charging should be
completed in the normal manner.
Fig. 7 Voltmeter - Typical
8F - 10 BATTERY SYSTEMRS
BATTERY (Continued)