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CHARGING SYSTEM
8C - 1
CHARGING SYSTEM
CONTENTS
page
page
DESCRIPTION AND OPERATION
BATTERY TEMPERATURE SENSOR . . . . . . . . . .
CHARGING SYSTEM . . . . . . . . . . . . . . . . . . . . . .
ELECTRONIC VOLTAGE REGULATOR . . . . . . . . .
GENERATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DIAGNOSIS AND TESTING
BATTERY TEMPERATURE SENSOR . . . . . . . . . .
CHARGING SYSTEM . . . . . . . . . . . . . . . . . . . . . .
2
1
2
1
3
2
ON-BOARD DIAGNOSTIC TEST FOR
CHARGING SYSTEM . . . . . . . . . . . . . . . . . . . .
REMOVAL AND INSTALLATION
BATTERY TEMPERATURE SENSOR . . . . . . . . . .
GENERATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SPECIFICATIONS
GENERATOR RATINGS . . . . . . . . . . . . . . . . . . . .
TORQUE CHART . . . . . . . . . . . . . . . . . . . . . . . . .
3
4
3
5
5
DESCRIPTION AND OPERATION
CHARGING SYSTEM
DESCRIPTION
The charging system consists of:
•
Generator
•
Electronic Voltage Regulator (EVR) circuitry
within the Powertrain Control Module (PCM)
•
Ignition switch (refer to Group 8D, Ignition Sys-
tem for information)
•
Battery (refer to Group 8A, Battery for informa-
tion)
•
Battery temperature sensor
•
Generator Lamp (if equipped)
•
Check Gauges Lamp (if equipped)
•
Voltmeter (refer to Group 8E, Instrument Panel
and Gauges for information)
•
Wiring harness and connections (refer to Group
8W, Wiring for information)
OPERATION
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. When the
ASD relay is on, voltage is supplied to the ASD relay
sense circuit at the PCM. This voltage is connected
through the PCM and supplied to one of the genera-
tor field terminals (Gen. Source +) at the back of the
generator.
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.
A battery temperature sensor, located in the bat-
tery tray housing, is used to sense battery tempera-
ture. This temperature data, along with data from
monitored line voltage, 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 mag-
netic field. The PCM then compensates and regulates
generator current output accordingly.
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. Refer to
On-Board Diagnostics in Group 25, Emission Control
System for more DTC information.
The Check Gauges Lamp (if equipped) monitors:
charging system voltage,
engine coolant tempera-
ture and engine oil pressure. If an extreme condition
is indicated, the lamp will be illuminated. This is
done as reminder to check the three gauges. The sig-
nal to activate the lamp is sent via the CCD bus cir-
cuits. The lamp is located on the instrument panel.
Refer to Group 8E, Instrument Panel and Gauges for
additional information.
GENERATOR
DESCRIPTION
The generator is belt-driven by the engine using a
serpentine type drive belt. It is serviced only as a
complete assembly. If the generator fails for any rea-
son, the entire assembly must be replaced.
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.
8C - 2
CHARGING SYSTEM
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DESCRIPTION AND OPERATION (Continued)
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 vehicle electrical system
through the generator battery terminal.
Although the generators appear the same exter-
nally, different generators with different output rat-
ings are used on this vehicle. Be certain that the
replacement generator has the same output rating
and part number as the original unit. Refer to Gen-
erator Ratings in the Specifications section at the
back of this group for amperage ratings and part
numbers.
Noise emitting from the generator may be caused
by: worn, loose or defective bearings; a loose or defec-
tive drive pulley; incorrect, worn, damaged or misad-
justed fan drive belt; loose mounting bolts; a
misaligned drive pulley or a defective stator or diode.
refer to Charging System Operation for additional
information.
DIAGNOSIS AND TESTING
CHARGING SYSTEM
The following procedures may be used to diagnose
the charging system if:
•
the generator lamp (if equipped) is illuminated
with the engine running
•
the voltmeter (if equipped) does not register
properly
•
an undercharged or overcharged battery condi-
tion occurs.
Remember that an undercharged battery is often
caused by:
•
accessories being left on with the engine not
running
•
a faulty or improperly adjusted switch that
allows a lamp to stay on. See Ignition-Off Draw Test
in Group 8A, Battery for more information.
BATTERY TEMPERATURE SENSOR
DESCRIPTION
The battery temperature sensor is attached to the
battery tray located under the battery.
INSPECTION
To perform a complete test of the charging system,
refer to the appropriate Powertrain Diagnostic Proce-
dures service manual and the DRB scan tool. Per-
form the following inspections before attaching the
scan tool.
(1) Inspect the battery condition. Refer to Group
8A, Battery for procedures.
(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) 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
torque specifications.
(5) Inspect generator drive belt condition and ten-
sion. Tighten or replace belt as required. Refer to
Belt Tension Specifications in Group 7, Cooling Sys-
tem.
(6) Inspect automatic belt tensioner (if equipped).
Refer to Group 7, Cooling System for information.
(7) 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.
OPERATION
The battery temperature sensor is used to deter-
mine the battery temperature and control battery
charging rate. This temperature data, along with
data from monitored line voltage, is used by the PCM
to vary the battery charging rate. System voltage will
be higher at colder temperatures and is gradually
reduced at warmer temperatures.
ELECTRONIC VOLTAGE REGULATOR
DESCRIPTION
The Electronic Voltage Regulator (EVR) is not a
separate component. It is actually a voltage regulat-
ing circuit located within the Powertrain Control
Module (PCM). The EVR is not serviced separately. If
replacement is necessary, the PCM must be replaced.
OPERATION
The amount of DC current produced by the gener-
ator is controlled by EVR circuitry contained within
the PCM. This circuitry is connected in series with
the generators second rotor field terminal and its
ground.
Voltage is regulated by cycling the ground path to
control the strength of the rotor magnetic field. The
EVR circuitry monitors system line voltage and bat-
tery temperature (refer to Battery Temperature Sen-
sor for more information). It then compensates and
regulates generator current output accordingly. Also
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DIAGNOSIS AND TESTING (Continued)
CHARGING SYSTEM
8C - 3
BATTERY TEMPERATURE SENSOR
To perform a complete test of this sensor and its
circuitry, refer to the appropriate Powertrain Diag-
nostic Procedures manual. To test the sensor only,
refer to the following:
(1) The sensor is located under the battery and is
attached to the battery tray (Fig. 1). A two-wire pig-
tail harness is attached directly to the sensor. The
opposite end of this harness connects the sensor to
the engine wiring harness.
For DTC information, refer to Diagnostic Trouble
Codes in Group 25, Emission Control System. This
will include a complete list of DTC’s including DTC’s
for the charging system.
REMOVAL AND INSTALLATION
GENERATOR
REMOVAL
WARNING: DISCONNECT NEGATIVE CABLE FROM
BATTERY BEFORE REMOVING BATTERY OUTPUT
WIRE (B+ WIRE) FROM GENERATOR. FAILURE TO
DO SO CAN RESULT IN INJURY OR DAMAGE TO
ELECTRICAL SYSTEM.
(1) Disconnect negative battery cable at battery.
(2) Remove generator drive belt. Refer to Group 7,
Cooling System for procedures.
(3) Left Hand Drive (LHD) Vehicles Only: Remove
generator pivot and mounting bolts/nut (Fig. 2) or
(Fig. 3). Position generator for access to wire connec-
tors.
(4) Right Hand Drive (RHD) Vehicles Only:
Remove upper nut (generator adjustment nut) and
both belt adjustment bolts (Fig. 4). Remove generator
lower nut/bolt. Position generator for access to wire
connectors.
(5) If equipped, unsnap plastic cover from B+ ter-
minal.
(6) Remove B+ terminal mounting nut at rear of
generator (Fig. 5). Disconnect terminal from genera-
tor.
(7) Disconnect field wire connector at rear of gen-
erator by pushing on connector tab.
(8) Remove generator from vehicle.
Fig. 1 Battery Temperature Sensor
(2) Disconnect the two-wire pigtail harness from
the engine harness.
(3) Attach ohmmeter leads to the wire terminals of
the pigtail harness.
(4) At room temperature of 25° C (75–80° F), an
ohmmeter reading of 9,000 (9K) to 11,000 (11K) ohms
should be observed.
(5) If reading is above or below the specification,
replace the sensor.
(6) Refer to the Removal and Installation section
for procedures.
INSTALLATION
(1) Position generator to engine and snap field
wire connector into rear of generator.
(2) Install B+ terminal to generator mounting
stud. Tighten mounting nut to 8.5 N·m (75 in. lbs.)
torque.
(3) If equipped, snap plastic cover to B+ terminal.
(4) LHD Vehicles: Install generator fasteners and
tighten as follows:
•
Generator upper mounting bolt-55 N·m (41 ft.
lbs.) torque.
•
Generator lower pivot bolt/nut-55 N·m (41 ft.
lbs.) torque.
CAUTION: Never force a belt over a pulley rim
using a screwdriver. The synthetic fiber of the belt
can be damaged.
ON-BOARD DIAGNOSTIC TEST FOR CHARGING
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 On-Board Diagnostic
(OBD) system. Some circuits are checked continu-
ously and some are checked only under certain con-
ditions.
8C - 4
CHARGING SYSTEM
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REMOVAL AND INSTALLATION (Continued)
Fig. 4 Remove/Install Generator—4.0L Engine—RHD
Fig. 2 Remove/Install Generator—2.5L Engine
Fig. 5 Generator Connectors—Typical Bosch
(6) RHD Vehicles: Install upper nut (generator
adjustment nut) and both belt adjustment bolts.
Install generator lower nut/bolt.
(7) RHD Vehicles: On vehicles equipped with RHD,
the generator is used to adjust the serpentine belt.
Refer to Group 7, Cooling System for belt routing,
belt adjustment and bolt tightening procedures.
(8) Install negative battery cable to battery.
Fig. 3 Remove/Install Generator—4.0L Engine—LHD
CAUTION: When installing a serpentine accessory
drive belt, the belt MUST be routed correctly. The
water pump will be rotating in the wrong direction if
the belt is installed incorrectly, causing the engine
to overheat. Refer to belt routing label in engine
compartment, or refer to Belt Schematics in Group
7, Cooling System.
(5) LHD Vehicles: Install generator drive belt.
Refer to Group 7, Cooling System for procedures.
BATTERY TEMPERATURE SENSOR
The battery temperature sensor is located under
vehicle battery (Fig. 6) and is attached to a mounting
hole on battery tray.
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REMOVAL AND INSTALLATION (Continued)
CHARGING SYSTEM
8C - 5
(2) Disconnect sensor pigtail harness from engine
wire harness.
(3) Pry sensor straight up from battery tray
mounting hole.
INSTALLATION
(1) Feed pigtail harness through hole in top of bat-
tery tray and press sensor into top of battery tray.
(2) Connect pigtail harness.
(3) Install battery. Refer to Group 8A, Battery for
procedures.
SPECIFICATIONS
Fig. 6 Battery Temperature Sensor
REMOVAL
(1) Remove battery. Refer to Group 8A, Battery for
procedures.
GENERATOR RATINGS
TYPE
DENSO
PART NUMBER
56041822AA
RATED SAE AMPS
124
ENGINES
2.5L/4.0L
MINIMUM TEST AMPS
90
TORQUE CHART
Right Hand Drive= RHD, Left Hand Drive= LHD.
Description
Torque
Generator Mounting Bolt—LHD—
2.5L/4.0L Engine . . . . . . . . . . 55 N·m (41 ft. lbs.)
Generator Pivot Bolt/Nut—LHD—
2.5L/4.0L Engine . . . . . . . . . . 55 N·m (41 ft. lbs.)
Battery Terminal Nut—LHD or RHD . . . . . 8.5 N·m
(75 in. lbs.)
Description
Torque
Ground Terminal Nut—LHD or RHD . . . . . 8.5 N·m
(75 in. lbs.)
Harness Hold-down Nut—LHD or RHD . . . 8.5 N·m
(75 in. lbs.)
Field Terminal Nuts—LHD or RHD . . . . . . 2.8 N·m
(25 in. lbs.)

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