exj_8c.pdf

CHARGING SYSTEM

8C - 1

CHARGING SYSTEM

TABLE OF CONTENTS

page

DESCRIPTION AND OPERATION

CHARGING SYSTEM.......................1

GENERATOR .............................1

BATTERY TEMPERATURE SENSOR ...........2

ELECTRONIC VOLTAGE REGULATOR ..........2

DIAGNOSIS AND TESTING

CHARGING SYSTEM.......................2

ON-BOARD DIAGNOSTIC TEST FOR

CHARGING SYSTEM .....................3

REMOVAL AND INSTALLATION

GENERATOR .............................3

BATTERY TEMPERATURE SENSOR ...........5

SPECIFICATIONS

GENERATOR RATINGS .....................5

TORQUE CHART ..........................5

DESCRIPTION AND OPERATION

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.

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-

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

8C - 2

CHARGING SYSTEM

DESCRIPTION AND OPERATION (Continued)

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 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.

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 (B+) and

battery temperature (refer to Battery Temperature

Sensor for more information). It then determines a

target charging voltage. If sensed battery voltage is

0.5 volts or lower than the target voltage, the PCM

grounds the field winding until sensed battery volt-

age is 0.5 volts above target voltage. A circuit in the

PCM cycles the ground side of the generator field up

to 100 times per second (100Hz), but has the capabil-

ity to ground the field control wire 100% of the time

(full field) to achieve the target voltage. If the charg-

ing rate cannot be monitored (limp-in), a duty cycle

of 25% is used by the PCM in order to have some

generator

BATTERY TEMPERATURE SENSOR

output.

Also

refer

Charging

System

Operation for additional information.

DESCRIPTION

The Battery Temperature Sensor (BTS) is attached

to the battery tray located under the battery.

DIAGNOSIS AND TESTING

CHARGING SYSTEM

The following procedures may be used to diagnose

the charging system if:

OPERATION

The BTS is used to determine the battery temper-

ature and control battery charging rate. This temper-

ature 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.

The PCM sends 5 volts to the sensor and is

grounded through the sensor return line. As temper-

ature increases, resistance in the sensor decreases

and the detection voltage at the PCM increases.

The BTS is also used for OBD II diagnostics. Cer-

tain faults and OBD II monitors are either enabled

or disabled, depending upon BTS input (for example,

disable purge and enable Leak Detection Pump

(LDP) and O2 sensor heater tests). Most OBD II

monitors are disabled below 20°F.

the generator lamp (if equipped) is illuminated

with the engine running

the

voltmeter

(if

equipped)

does

not

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.

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.

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.

CHARGING SYSTEM

8C - 3

DIAGNOSIS AND TESTING (Continued)

(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.

(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. 1) or

(Fig. 2). 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. 3). 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. 4). 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.

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.

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.

Fig. 1 Remove/Install Generator—2.5L Engine

1 – UPPER MOUNTING BRACKET

2 – GENERATOR

3 – UPPER BOLT

4 – LOWER BOLT

8C - 4

CHARGING SYSTEM

REMOVAL AND INSTALLATION (Continued)

Fig. 4 Generator Connectors—Typical Denso

1 – FIELD WIRES

2 – B+ (OUTPUT TERMINAL)

3 – FIELD WIRE CONNECTOR

Fig. 2 Remove/Install Generator—4.0L Engine—LHD

1 – UPPER MOUNTING BRACKET

2 – GENERATOR

3 – UPPER BOLT

4 – LOWER BOLT

(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.

INSTALLATION

(1) Position

Generator lower pivot bolt/nut-55 N·m (41 ft.

lbs.) torque.

generator

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.

CAUTION: Never force a belt over a pulley rim

using a screwdriver. The synthetic fiber of the belt

can be damaged.

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.

(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—RHD

1 – UPPER NUT

2 – LOWER BOLT

3 – GENERATOR

4 – BELT ADJUSTMENT BOLTS

CHARGING SYSTEM

8C - 5

REMOVAL AND INSTALLATION (Continued)

BATTERY TEMPERATURE SENSOR

The battery temperature sensor is located under

vehicle battery (Fig. 5) and is attached to a mounting

hole on battery tray.

REMOVAL

(1) Remove battery. Refer to Group 8A, Battery for

procedures.

(2) Disconnect sensor pigtail harness from engine

wire harness.

(3) Pry

sensor

straight

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.

Fig. 5 Battery Temperature Sensor

1 – BATTERY TEMPERATURE SENSOR

2 – BATTERY TRAY

SPECIFICATIONS

GENERATOR RATINGS

TYPE

PART NUMBER

RATED SAE AMPS

ENGINES

MINIMUM TEST AMPS

DENSO

56041685AA

117

4.0L

DENSO

56041565AA

4.0L

DENSO

56005684AB

2.5L

DENSO

56005685AC

117

2.5L

DENSO

56041822AA

124

2.5L/4.0L

TORQUE CHART

Right Hand Drive= RHD, Left Hand Drive= LHD.

Description

Torque

Ground Terminal Nut—LHD or

RHD .................. 8.5N·m(75in.lbs.)

Harness Hold-down Nut—LHD or

RHD .................. 8.5N·m(75in.lbs.)

Field Terminal Nuts—LHD or

RHD .................. 2.8N·m(25in.lbs.)

Description

Torque

Generator Mounting Bolt—LHD—2.5L/4.0L

Engine .................. 55N·m(41ft.lbs.)

Generator Pivot Bolt/Nut—LHD—2.5L/4.0L

Engine .................. 55N·m(41ft.lbs.)

Battery Terminal Nut—LHD or

RHD .................. 8.5N·m(75in.lbs.)

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