belt CHRYSLER VOYAGER 2004 Workshop Manual

INSTALLATION
(1) Connect the module wire harness connectors.
(2) Snap the module on the seat cushion pan.
(3) Install the appropriate front seat in the vehicle
(Refer to 23 - BODY/SEATS/SEAT - INSTALLA-
TION).
(4) Connect and isolate the negative battery cable.
MEMORY SEAT/MIRROR
MODULE
DESCRIPTION
Vehicles equipped with the memory seat/mirror
option, utilize a memory module located under the
drivers front seat. This module is basically wired in-
line between the power seat switch and the power
seat track/adjuster motors, or in-line between the
power mirror switch and the power side view mir-
ror(s) motor(s). The MSMM contains a central pro-
cessing unit that communicates with other modules
on the Programmable Communications Interface
(PCI) data bus network.
The Memory Seat/Mirror Module (MSMM) receives
hard wired inputs from the driver power seat switch
and the potentiometers on each of the driver side
power seat track motors, or from the power mirror
switch and the potentiometers on the side view mir-
ror. The MSMM receives messages over the PCI data
bus from the Body Control Module (BCM) (memory
switch status), the Powertrain Control Module (PCM)
(vehicle speed status). The MSMM will prevent the
seat memory recall function from being initiated if
the driver side seat belt is buckled, if the transmis-
sion gear selector lever is not in the Park or Neutral
positions, or if the vehicle is moving.
For diagnosis of the MSMM or the PCI data bus, a
DRB IIItscan tool and the proper Diagnostic Proce-
dures manual are recommended. The MSMM cannot
be repaired and, if faulty or damaged, it must be
replaced. Refer toMemory Systemin the Power
Seat or Power Mirror section of this manual for more
information on the memory system option.
OPERATION
When memory system operation is requested
(depressing of the memory switch), a resistor multi-
plexed signal is sent from the memory switch to the
body control module (BCM). The body control module
will then send the appropriate signals out to the
memory/mirror seat module, the memory/mirror seat
module then applies the voltage supply to the power
seat track or side-view mirror if the proper require-
ments are met. The vehicle speed must equal zero
and the transmission must be in park or neutral in
order for the memory system to function.
DIAGNOSIS AND TESTING - MEMORY
SEAT/MIRROR MODULE
Visually inspect the related wiring harness connec-
tors. Look for broken, bent, pushed out, or corroded
terminals. If any of the above conditions are present,
repair as necessary. If not, use a DRB IIItscan tool
and the proper Diagnostic Procedures Manual to test
the memory/mirror seat module. For complete circuit
diagrams, refer toWiring Diagrams.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the driver side front bucket seat
retaining nuts from under the vehicle (Refer to 23 -
BODY/SEATS/SEAT - REMOVAL).
(3) Lift the drivers seat up and out of the mount-
ing holes in the floor pan and lay the seat rearward
to access the module located under the seat. It is not
necessary to disconnect the seat electrical, just use
care not to damage the wiring by over-extending.
(4) Disconnect the memory/mirror seat module
electrical connectors. Depress the retaining tab and
pull straight apart.
(5) Remove the module retaining bolts and remove
the module from the bracket.
INSTALLATION
(1) Position and install the module retaining bolts.
(2) Connect the memory/mirror seat module elec-
trical connectors.
(3) Position the drivers seat in the mounting holes
in the floor pan.
(4) Install the driver side front bucket seat retain-
ing nuts from under the vehicle (Refer to 23 - BODY/
SEATS/SEAT - INSTALLATION).
(5) Connect the battery negative cable.
POWER LIFTGATE CONTROL
MODULE
DESCRIPTION
Vehicles equipped with a power liftgate (PLG) uti-
lize a PLG control module. This module is located on
the vehicles left side D-pillar just below the motor
assembly (Fig. 8) and contains a microprocessor,
which is used to communicate to the vehicles body
control module. The PLG control module receives and
monitors logic inputs from all the PLG system
switches except for the outside handle switch. This
module also contains the software technology to
detect liftgate obstructions and stop and/or reverse
the door accordingly.
8E - 10 ELECTRONIC CONTROL MODULESRS
HEATED SEAT MODULE (Continued)

CHARGING
TABLE OF CONTENTS
page page
CHARGING
DESCRIPTION - CHARGING SYSTEM.......20
OPERATION - CHARGING SYSTEM.........20
DIAGNOSIS AND TESTING - ON-BOARD
DIAGNOSTIC SYSTEM.................21
SPECIFICATIONS
GENERATOR........................22
TORQUE............................22
SPECIFICATIONS - BATTERY
TEMPERATURE SENSOR...............22
SPECIAL TOOLS.......................23
BATTERY TEMPERATURE SENSOR
DESCRIPTION.........................23
OPERATION...........................23
REMOVAL.............................23
GENERATOR
DESCRIPTION.........................23OPERATION...........................23
REMOVAL
REMOVAL - 2.4L......................23
REMOVAL - 3.3/3.8L...................24
INSTALLATION
INSTALLATION - 2.4L..................24
INSTALLATION - 3.3/3.8L................24
GENERATOR DECOUPLER PULLEY
DESCRIPTION.........................25
OPERATION...........................25
DIAGNOSIS AND TESTING - GENERATOR
DECOUPLER PULLEY..................25
REMOVAL.............................26
INSTALLATION.........................26
VOLTAGE REGULATOR
DESCRIPTION.........................27
OPERATION...........................27
CHARGING
DESCRIPTION - CHARGING SYSTEM
The charging system consists of:
²Generator
²Decoupler Pulley (If equipped)
²Electronic Voltage Regulator (EVR) circuitry
within the Powertrain Control Module (PCM)
²Ignition switch (refer to the Ignition System sec-
tion for information)
²Battery (refer to the Battery section for informa-
tion)
²Ambient Air Temperature (If equipped)
²Inlet Air Temperature (calculated battery tem-
perature)(If equipped)
²Voltmeter (refer to the Instrument Cluster sec-
tion for information if equipped)
²Wiring harness and connections (refer to the
Wiring section for information)
²Accessory drive belt (refer to the Cooling section
for more information)
²Battery Temperature sensor (if equipped)
OPERATION - CHARGING SYSTEM
The charging system is turned on and off with the
ignition switch. The system is on when the engine is
running and the ASD relay is energized. The ASD
relay is energized when the PCM grounds the ASD
control circuit. (SBEC vehicles) This voltage is con-
nected through the PCM or IPM (intelligent powermodule) (if equipped) and supplied to one of the gen-
erator field terminals (Gen. Source +) at the back of
the generator.
The generator is driven by the engine through a
serpentine belt and pulley or decoupler pulley
arrangement.
The amount of DC current produced by the gener-
ator is controlled by the EVR (field control) circuitry
contained within the PCM. This circuitry is con-
nected in series with the second rotor field terminal
and ground.
(SBEC vehicles) An Inlet air temperature sensor is
used to calculate the temperature near the battery.
This temperature data, along with data from moni-
tored line voltage (battery voltage sense circuit), is
used by the PCM to vary the battery charging rate.
This is done by cycling the ground path to control the
strength of the rotor magnetic field. The PCM then
compensates and regulates generator current output
accordingly to maintain system voltage at the tar-
geted system voltage based on battery temperature.
All vehicles are equipped with On-Board Diagnos-
tics (OBD). All OBD-sensed systems, including EVR
(field control) circuitry, 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 certain failures it detects and
illuminate the (MIL) lamp. Refer to On-Board Diag-
nostics in the Electronic Control Modules(Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
8F - 20 CHARGINGRS

ULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION) section for more DTC information.
The Check Gauges Lamp (if equipped) or Battery
Lamp monitors:charging system voltage,engine
coolant temperature and engine oil pressure. If an
extreme condition is indicated, the lamp will be illu-
minated. The signal to activate the lamp is sent via
the PCI bus circuits. The lamp is located on the
instrument panel. Refer to the Instrument Cluster
section for additional information.
(If equipped with inlet air temperature sensor) The
PCM uses the inlet air temperature sensor to control
the charge system voltage. This temperature, along
with data from monitored line voltage, is used by the
PCM to vary the battery charging rate. The system
voltage is higher at cold temperatures and is gradu-
ally reduced as the calculated battery temperature
increases.
The ambient temperature sensor is used to control
the battery voltage based upon ambient temperature
(approximation of battery temperature). The PCM
maintains the optimal output of the generator by
monitoring battery voltage and controlling it to a
range of 13.5 - 14.7 volts based on battery tempera-
ture. The system target voltage is 13.5 ± 14.7 volts.
However the actual voltage go below this during
heavy electrical loads and generator speeds. Also the
actual voltage can be lower than the target voltage
between the battery and the battery voltage sense
circuit, approximately 0.2 Ð 0.3 volts.
DIAGNOSIS AND TESTING - ON-BOARD
DIAGNOSTIC SYSTEM
The Powertrain Control Module (PCM) monitors
critical input and output circuits of the charging sys-
tem, making sure they are operational. A Diagnostic
Trouble Code (DTC) is assigned to each input and
output circuit monitored by the OBD system. Some
circuits are checked continuously and some are
checked only under certain conditions.
If the OBD system senses that a monitored circuit
is bad, it will put a DTC into electronic memory. The
DTC will stay in electronic memory as long as the
circuit continues to be bad. The PCM is programmed
to clear the memory after 40 good trip if the problem
does not occur again.
DIAGNOSTIC TROUBLE CODES
A DTC description can be read using the DRBIIIt
scan tool. Refer to the appropriate Powertrain Diag-
nostic Procedures manual for information.
A DTC does not identify which component in a cir-
cuit is bad. Thus, a DTC should be treated as a
symptom, not as the cause for the problem. In some
cases, because of the design of the diagnostic test
procedure, a DTC can be the reason for another DTCto be set. Therefore, it is important that the test pro-
cedures be followed in sequence, to understand what
caused a DTC to be set.
ERASING DIAGNOSTIC TROUBLE CODES
The DRBIIItScan Tool must be used to erase a
DTC.
The following procedures may be used to diagnose
the charging system if:
²the check gauges lamp or battery lamp is illumi-
nated with the engine running
²the voltmeter (if equipped) does not register
properly
²an undercharged or overcharged battery condi-
tion occurs.
Remember that an undercharged battery is often
caused by:
²accessories being left on with the engine not
running
²a faulty or improperly adjusted switch that
allows a lamp to stay on. Refer to Ignition-Off Draw
Test (Refer to 8 - ELECTRICAL/BATTERY SYSTEM/
BATTERY - STANDARD PROCEDURE)
²loose generator belt.
INSPECTION
The Powertrain Control Module (PCM) monitors
critical input and output circuits of the charging sys-
tem, making sure they are operational. A Diagnostic
Trouble Code (DTC) is assigned to each input and
output circuit monitored by the On-Board Diagnostic
(OBD) system. Some charging system circuits are
checked continuously, and some are checked only
under certain conditions.
Refer to Diagnostic Trouble Codes in; Powertrain
Control Module; Electronic Control Modules for more
DTC information. This will include a complete list of
DTC's including DTC's for the charging system.
To perform a complete test of the charging system,
refer to the appropriate Powertrain Diagnostic Proce-
dures service manual and the DRBIIItscan tool.
Perform the following inspections before attaching
the scan tool.
(1) Inspect the battery condition. Refer to the Bat-
tery section (Refer to 8 - ELECTRICAL/BATTERY
SYSTEM - DIAGNOSIS AND TESTING) for proce-
dures.
(2) Inspect condition of battery cable terminals,
battery posts, connections at engine block, starter
solenoid and relay. They should be clean and tight.
Repair as required.
(3) Inspect all fuses in both the fuseblock and
Power Distribution Center (PDC) or IPM (if
equipped) for tightness in receptacles. They should be
properly installed and tight. Repair or replace as
required.
RSCHARGING8F-21
CHARGING (Continued)

(4) Inspect generator mounting bolts for tightness.
Replace or tighten bolts if required. Refer to the Gen-
erator Removal/Installation section of this group for
torque specifications (Refer to 8 - ELECTRICAL/
CHARGING - SPECIFICATIONS).
(5) Inspect generator drive belt condition and ten-
sion. Tighten or replace belt as required. Refer to
Belt Tension Specifications(Refer to 7 - COOLING/
ACCESSORY DRIVE - SPECIFICATIONS).
(6) Inspect decoupler pulley (if equipped). Ensure
decoupler pulley is driving the alternator rotor.
(7) Inspect automatic belt tensioner (if equipped).
Refer to the Cooling System for more information.
(8) Inspect generator electrical connections at gen-
erator field, battery output, and ground terminal (if
equipped). Also check generator ground wire connec-
tion at engine (if equipped). They should all be clean
and tight. Repair as required.SPECIFICATIONS
GENERATOR
Type Engine Minimun Test
Amperage
Denso 2.4 L 80 Amp (HOT)
Denso 3.3/3.8L 100 Amp or 115
Amp (HOT)
Test Specification:
1. Engine RPM : 2500 RPM  20 RPM (HOT)
2. Voltage Output : 14.0 V   0.5 V
3. Field Current : 5 amps   0.1 amps
Part number is located on the side of the generator.
TORQUE
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Battery Hold Down Clamp
Bolt20 14.7 180
Generator B+ Nut 12.4 9.2 110
Battery Terminal Nut 4 35
Generator Mounting Bolt
2.4L28.2 20.8 250
Generator Mounting Bolts
3.3/3.8L54.2 40
Starter Solenoid Battery
Nut 3.3/3.8L11.3 8.3 100
Generator Decoupler 109.8 81
SPECIFICATIONS - BATTERY TEMPERATURE SENSOR
ÉC ÉF K-Ohms Min. K-Ohms Max.
(40) (40) 291.4 381.7
(20) (4) 85.8 108.4
20 68 11.4 13.6
25 77 9.1 10.9
120 248 0.37 0.41
130 266 0.28 0.32
8F - 22 CHARGINGRS
CHARGING (Continued)

SPECIAL TOOLS
BATTERY TEMPERATURE
SENSOR
DESCRIPTION
(NGC Vehicles) The PCM incorporates a Battery
Temperature Sensor (BTS) on its circuit board.
OPERATION
The PCM uses the temperature of the battery area
to control the charge system voltage. This tempera-
ture, along with data from monitored line voltage, is
used by the PCM to vary the battery charging rate.
The system voltage is higher at cold temperatures
and is gradually reduced as temperature around the
battery increases.
(NGC Vehicles) The ambient temperature sensor is
used to control the battery voltage based upon ambi-
ent temperature (approximation of battery tempera-
ture). The PCM maintains the optimal output of the
generator by monitoring battery voltage and control-
ling it to a range of 13.5 - 14.7 volts based on battery
temperature. The system target voltage is 13.5 ± 14.7
volts. However the actual voltage go below this dur-
ing heavy electrical loads and generator speeds. Also
the actual voltage can be lower than the target volt-
age between the battery and the battery voltage
sense circuit, approximately 0.2 Ð 0.3 volts.
The battery temperature sensor is also used for
OBD II diagnostics. Certain faults and OBD II mon-
itors are either enabled or disabled depending upon
the battery temperature sensor input (example: dis-
able purge and EGR, enable LDP). Most OBD II
monitors are disabled below 20ÉF.
REMOVAL
The battery temperature sensor is not serviced sep-
arately. If replacement is necessary, the PCM must
be replaced.
GENERATOR
DESCRIPTION
The generator is belt-driven by the engine. The
generator produces DC voltage at the B+ terminal. If
the generator is failed, the generator assembly sub-
components (generator and decoupler pulley) must be
inspected for individual failure and replaced accord-
ingly.
OPERATION
As the energized rotor begins to rotate within the
generator, the spinning magnetic field induces a cur-
rent into the windings of the stator coil. Once the
generator begins producing sufficient current, it also
provides the current needed to energize the rotor.
The Y type stator winding connections deliver the
induced AC current to 3 positive and 3 negative
diodes for rectification. From the diodes, rectified DC
current is delivered to the vehicles electrical system
through the generator, battery, and ground terminals.
Excessive or abnormal noise emitting from the gen-
erator may be caused by:
²Worn, loose or defective bearings
²Loose or defective drive pulley (2.4L) or decou-
pler (3.3/3.8L)
²Incorrect, worn, damaged or misadjusted drive
belt
²Loose mounting bolts
²Misaligned drive pulley
²Defective stator or diode
²Damaged internal fins
REMOVAL
REMOVAL - 2.4L
(1) Release hood latch and open hood.
(2) Disconnect battery negative cable.
(3) Disconnect the Inlet Air Temperature sensor.
(4) Remove the Air Box, refer to the Engine/Air
Cleaner for more information.
(5) Remove the EVAP Purge solenoid from its
bracket and reposition.
(6) Disconnect the push-in field wire connector
from back of generator.
(7) Remove nut holding B+ wire terminal to back
of generator.
(8) Separate B+ terminal from generator.
(9) Remove accessory drive belt, refer to the Cool-
ing System section for proper procedures.
(10) Remove the generator.
GENERATOR DECOUPLER 8433
RSCHARGING8F-23
CHARGING (Continued)

REMOVAL - 3.3/3.8L
(1) Release hood latch and open hood.
(2) Disconnect battery negative cable.
(3) Disconnect the push-in field wire connector
from back of generator.
(4) Remove nut holding B+ wire terminal to back
of generator.
(5) Separate B+ terminal from generator.
(6) Raise vehicle and support.
(7) Remove the right front lower splash shield.
(8) Remove accessory drive belt, refer to the Cool-
ing System section for proper procedures.
(9) Remove the lower oil dip stick tube bolt (Fig.
1).
(10) Remove wiring harness from the oil dip stick
tube
(11) Remove the 3 mounting bolts.
(12) Lower vehicle.
(13) Remove oil dip stick tube from vehicle.
(14) Roll and remove the generator from vehicle
(Fig. 2).
INSTALLATION
INSTALLATION - 2.4L
(1) Install the generator.
(2) Install the accessory drive belt, refer to the
Cooling System section for proper procedures.
(3) Connect B+ terminal to generator.
(4) Install nut holding B+ wire terminal to back of
generator.(5) Connect the push-in field wire connector to
back of generator.
(6) Install the EVAP Purge solenoid to its bracket.
(7) Install the Air Box, refer to the Engine/Air
Cleaner for more information.
(8) Connect the Inlet Air Temperature sensor.
(9) Connect battery negative cable.
INSTALLATION - 3.3/3.8L
(1) Roll and place generator in position on vehicle
(Fig. 2).
(2) Install upper bolts to hold generator in place.
(3) Lubricate the o-ring. Install oil dip stick tube.
(4) Install the upper oil dip stick tube bolt.
(5) Place B+ terminal in position on generator.
(6) Install nut to hold B+ wire terminal to back of
generator.
(7) Connect the push-in field wire connector into
back of generator.
(8) Raise vehicle and support.
(9) Install the lower mounting bolt and tighten.
(10) Install the lower oil dip stick tube bolt and
tighten (Fig. 1).
(11) Install accessory drive belt, refer to the Cool-
ing System section for proper procedures.
(12) Install the right front lower splash shield.
(13) Lower vehicle.
(14) Install wiring harness to the oil dip stick tube
(15) Connect battery negative cable.
(16) Verify generator output rate.
Fig. 1 DIP STICK LOWER BOLT
Fig. 2 GENERATOR 3.3/3.8L
8F - 24 CHARGINGRS
GENERATOR (Continued)

GENERATOR DECOUPLER
PULLEY
DESCRIPTION
The Generator Decoupler is a one way clutch (Fig.
3). It is attached to the generator and replaces the
standard pulley. It is a non-serviceable item and is to
be replaced as an assembly. It is a dry operation (no
grease or lubricants). The operation of it is not tem-
perature sensitive and has a low sensitivity to elec-
trical load.
OPERATION
The generator decoupler is a one way clutch and
should be replaced as an assembly. It is designed to
help reduce belt tension fluctuation, reduce fatigue
loads, improve belt life, reduce hubloads on compo-
nents, and reduce noise.
DIAGNOSIS AND TESTING - GENERATOR DECOUPLER PULLEY
CONDITION VERIFICATION PROCEDURE POSSIBLE CAUSES CORRECTION
Does not drive
generator (Generator
not Charging)1. Start engine and allow
engine to idle.Clutch failure Replace Decoupler
2.Verify generator pulley is
rotating.
3. View generator internal fins
thru generator housing.
4. Fins either do not rotate or
rotate very erratic.
5. Rotate decoupler pulley in
clockwise direction then
quickly rotate in
counterclockwise direction to
see if clutch engages.
Noise from generator
at engine shut down.1. Start engine and allow
engine to idle.Defective decoupler
pulley bearing.Replace decoupler pulley.
2. Shutdown engine and listen
to generator.
3. Noise heard just as engine
stops. Sounds like a click.
4. Remove accessory drive
belt.
5. Verify rotation in
counterclock wise direction is
rough.
Fig. 3 GENERATOR DECOUPLER 3.3/3.8L
RSCHARGING8F-25

REMOVAL
(1) Release hood latch and open hood.
(2) Disconnect battery negative cable.
(3) Raise vehicle and support.
(4) Remove the right front lower splash shield.
(5) Remove accessory drive belt, refer to the Cool-
ing System section for proper procedures (Fig. 4).
(6) Lower vehicle.
(7) Remove the Air Box, refer to the Engine section
for more information.
(8) Remove the decoupler pulley cover.
(9) Use Special Tool #8433 (Fig. 6) to loosen the
Generator Decoupler (Fig. 5).
(10) Remove the tool.
(11) Remove the Generator Decoupler.
INSTALLATION
(1) Install the Generator Decoupler to the genera-
tor shaft.
(2) Use Special Tool #8433 (Fig. 6) to tighten the
Generator Decoupler (Fig. 7). Refer to the torque
chart for the proper torque.
(3) Install a new decoupler pulley cover.
(4) Install the Air Box, refer to the Engine section
for more information.(5) Raise vehicle and support.
(6) Install accessory drive belt, refer to the Cooling
System section for proper procedures (Fig. 4).
(7) Install the right front lower splash shield.
(8) Lower vehicle.
(9) Connect battery negative cable.
Fig. 4 DRIVE BELT 3.3/3.8L
Fig. 5 DECOUPLER REMOVAL (LITENS)
Fig. 6 SPECIAL TOOL 8433 AND DECOUPLER
8F - 26 CHARGINGRS
GENERATOR DECOUPLER PULLEY (Continued)

CHARGING
TABLE OF CONTENTS
page page
CHARGING DESCRIPTION - CHARGING SYSTEM .......20
OPERATION - CHARGING SYSTEM .........20
DIAGNOSIS AND TESTING - ON-BOARD DIAGNOSTIC SYSTEM .................21
SPECIFICATIONS GENERATOR ........................22
TORQUE ............................22
SPECIFICATIONS - BATTERY TEMPERATURE SENSOR ...............22
SPECIAL TOOLS .......................23
BATTERY TEMPERATURE SENSOR DESCRIPTION .........................23
OPERATION ...........................23
REMOVAL .............................23
GENERATOR DESCRIPTION .........................23
OPERATION ...........................23 REMOVAL
REMOVAL - 2.4L ......................23
REMOVAL - 2.5L ......................24
REMOVAL - 3.3/3.8L ...................25
INSTALLATION INSTALLATION - 2.4L ..................26
INSTALLATION - 2.5L ..................26
INSTALLATION - 3.3/3.8L ................26
GENERATOR DECOUPLER PULLEY DESCRIPTION .........................27
OPERATION ...........................27
DIAGNOSIS AND TESTING - GENERATOR DECOUPLER PULLEY ..................27
REMOVAL .............................28
INSTALLATION .........................28
VOLTAGE REGULATOR DESCRIPTION .........................29
OPERATION ...........................29
CHARGING
DESCRIPTION - CHARGING SYSTEM
The charging system consists of:
²Generator
² Decoupler Pulley (If equipped)
² Electronic Voltage Regulator (EVR) circuitry
within the Powertrain Control Module (PCM) ² Ignition switch (refer to the Ignition System sec-
tion for information) ² Battery (refer to the Battery section for informa-
tion) ² Ambient Air Temperature (If equipped)
² Inlet Air Temperature (calculated battery tem-
perature)(If equipped) ² Voltmeter (refer to the Instrument Cluster sec-
tion for information if equipped) ² Wiring harness and connections (refer to the
Wiring section for information) ² Accessory drive belt (refer to the Cooling section
for more information) ² Battery Temperature sensor (if equipped)
OPERATION - CHARGING SYSTEM
The charging system is turned on and off with the
ignition switch. The system is on when the engine is
running and the ASD relay is energized. The ASD
relay is energized when the PCM grounds the ASD
control circuit. This voltage is connected through the PCM or IPM (intelligent power module) (if equipped)
and supplied to one of the generator field terminals
(Gen. Source +) at the back of the generator.
The generator is driven by the engine through a
serpentine belt and pulley or decoupler pulley
arrangement. The amount of DC current produced by the gener-
ator is controlled by the EVR (field control) circuitry
contained within the PCM. This circuitry is con-
nected in series with the second rotor field terminal
and ground. An Ambient air temperature sensor is used to cal-
culate the temperature near the battery. This tem-
perature data, along with data from monitored line
voltage (battery voltage sense circuit), is used by the
PCM to vary the battery charging rate. This is done
by cycling the ground path to control the strength of
the rotor magnetic field. The PCM then compensates
and regulates generator current output accordingly
to maintain system voltage at the targeted system
voltage based on battery temperature. All vehicles are equipped with On-Board Diagnos-
tics (OBD). All OBD-sensed systems, including EVR
(field control) circuitry, 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 certain failures it detects and
illuminate the (MIL) lamp. Refer to On-Board Diag-
nostics in the Electronic Control Modules(Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
8Fs - 20 CHARGINGRS

ULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION) section for more DTC information.The Charging system ªBatteryº light indicates
problems with the charging system (voltage too high/
low, generator failure, etc.). If an extreme condition is
indicated, the lamp will be illuminated. The signal to
activate the lamp is sent via the PCI bus circuits.
The lamp is located on the instrument panel. Refer
to the Instrument Cluster section for additional infor-
mation. The PCM uses the ambient air temperature sensor
to control the charge system voltage. This tempera-
ture, along with data from monitored line voltage, is
used by the PCM to vary the battery charging rate.
The system voltage is higher at cold temperatures
and is gradually reduced as the calculated battery
temperature increases. The ambient temperature sensor is used to control
the battery voltage based upon ambient temperature
(approximation of battery temperature). The PCM
maintains the optimal output of the generator by
monitoring battery voltage and controlling it to a
range of 13.5 - 14.7 volts based on battery tempera-
ture.
DIAGNOSIS AND TESTING - ON-BOARD
DIAGNOSTIC SYSTEM
The Powertrain Control Module (PCM) monitors
critical input and output circuits of the charging sys-
tem, making sure they are operational. A Diagnostic
Trouble Code (DTC) is assigned to each input and
output circuit monitored by the OBD system. Some
circuits are checked continuously and some are
checked only under certain conditions. If the OBD system senses that a monitored circuit
is bad, it will put a DTC into electronic memory. The
DTC will stay in electronic memory as long as the
circuit continues to be bad. The PCM is programmed
to clear the memory after 40 good trip if the problem
does not occur again.
DIAGNOSTIC TROUBLE CODES
A DTC description can be read using the DRBIII t
scan tool. Refer to the appropriate Powertrain Diag-
nostic Procedures manual for information. A DTC does not identify which component in a cir-
cuit is bad. Thus, a DTC should be treated as a
symptom, not as the cause for the problem. In some
cases, because of the design of the diagnostic test
procedure, a DTC can be the reason for another DTC
to be set. Therefore, it is important that the test pro-
cedures be followed in sequence, to understand what
caused a DTC to be set. ERASING DIAGNOSTIC TROUBLE CODES
The DRBIII tScan Tool must be used to erase a
DTC. The following procedures may be used to diagnose
the charging system if: ² the check gauges lamp or battery lamp is illumi-
nated with the engine running ² the voltmeter (if equipped) does not register
properly ² an undercharged or overcharged battery condi-
tion occurs. Remember that an undercharged battery is often
caused by: ² accessories being left on with the engine not
running ² a faulty or improperly adjusted switch that
allows a lamp to stay on. Refer to Ignition-Off Draw
Test (Refer t o 8 - ELECTRICAL/BATTERY SYSTEM/
BATTERY - STANDARD PROCEDURE) ² loose generator belt.
INSPECTION The Powertrain Control Module (PCM) monitors
critical input and output circuits of the charging sys-
tem, making sure they are operational. A Diagnostic
Trouble Code (DTC) is assigned to each input and
output circuit monitored by the On-Board Diagnostic
(OBD) system. Some charging system circuits are
checked continuously, and some are checked only
under certain conditions. Refer to Diagnostic Trouble Codes in; Powertrain
Control Module; Electronic Control Modules for more
DTC information. This will include a complete list of
DTC's including DTC's for the charging system. To perform a complete test of the charging system,
refer to the appropriate Powertrain Diagnostic Proce-
dures service manual and the DRBIII tscan tool.
Perform the following inspections before attaching
the scan tool. (1) Inspect the battery condition. Refer to the Bat-
tery section (Refer t o 8 - ELECTRICAL/BATTERY
SYSTEM - DIAGNOSIS AND TESTING) for proce-
dures. (2) Inspect condition of battery cable terminals,
battery posts, connections at engine block, starter
solenoid and relay. They should be clean and tight.
Repair as required. (3) Inspect all fuses in both the fuseblock and
Power Distribution Center (PDC) or IPM (if
equipped) for tightness in receptacles. They should be
properly installed and tight. Repair or replace as
required. (4) Inspect generator mounting bolts for tightness.
Replace or tighten bolts if required. Refer to the Gen-
erator Removal/Installation section of this group for
RS CHARGING8Fs-21
CHARGING (Continued)