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

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 mounted on

the bumper used to calculate the temperature near
the battery. This temperature 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 feed path
to control the strength of the rotor magnetic field.
The PCM then compensates and regulates generator
current output accordingly to maintain system volt-
age 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-

ULES/POWERTRAIN

CONTROL

MODULE

DESCRIPTION) section for more DTC information.

The Charging system “Battery” 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.

CHARGING

8F - 17

The PCM uses the inlet air temperature sensor or

ambient 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 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 main-
tains 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 temperature.

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

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

t Scan Tool must be used to erase a

DTC.

The following procedures may be used to diagnose

the charging system if:

• the check gauges lamp or battery lamp is illumi-

nated 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. Refer to Ignition-Off Draw
Test (Refer to 8 - ELECTRICAL/BATTERY SYSTEM/
BATTERY - STANDARD PROCEDURE)

• 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

t scan 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.

(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.

8F - 18

CHARGING

CHARGING (Continued)

SPECIFICATIONS

GENERATOR

Type

Engine

Minimun Test
Amperage

Denso

2.7L

105 Amp

Denso

3.5L

125 Amps

Test Specification:

1. Engine RPM : 2500 RPM ±20 RPM

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.

SPECIFICATIONS - TORQUE

TORQUE SPECIFICATIONS

DESCRIPTION

N·m

Ft. Lbs.

In. Lbs.

Battery Hold Down Clamp

Bolt

10.3

125

Generator Mounting Bolt 8

Generator Mounting Bolt

10 mm

Battery Terminal Nut

7.3

Generator B+ Terminal

9.8

85 ±15

Generator Pivot bolt Bolt 8

GENERATOR

DESCRIPTION

The generator is belt-driven by the engine. It is

serviced only as a complete assembly. If the genera-
tor fails for any reason, the entire assembly must be
replaced. The generator produces DC voltage.

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.

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.

Noise emitting from the generator may be caused

by:

• Worn, loose or defective bearings

• Loose or defective drive pulley

• Incorrect, worn, damaged or misadjusted drive

belt

• Loose mounting bolts

• Misaligned drive pulley

• Defective stator or diode

• Damaged internal fins

CHARGING

8F - 19

CHARGING (Continued)

REMOVAL

REMOVAL - 2.7L

(1) Disconnect negative battery cable.
(2) Raise and support vehicle.
(3) Remove lower plastic splash shield (Fig. 1).

(4) Remove transmission cooler and reposition

cooler out of the way.

(5) Remove lower radiator crossmember support

and position a jackstand under radiator for support.

(6) Loosen adjusting T-bolt, but do not remove.
(7) Loosen pivot bolt, but do not remove.
(8) Remove the generator drive belt. Refer to the

Cooling System section.

(9) Disconnect the generator field circuit plug.
(10) Remove the B+ terminal nut and wire.
(11) Remove pivot bolt, being careful not to lose

spacer.

(12) Remove generator.

REMOVAL - 3.5L

(1) Disconnect negative battery cable (Fig. 2).

(2) Loosen lower mounting bolt do not remove.
(3) Remove the upper radiator support and relo-

cate.

(4) Loosen the lower mounting bolt, but do not

remove

(5) Loosen pivot bolt, but do not remove.
(6) Loosen belt adjustment bolt.
(7) Remove the generator drive belt. Refer to the

Cooling System section.

(8) Remove lower mounting bolt.
(9) Disconnect the generator field circuit plug.
(10) Remove the B+ terminal nut and wire.
(11) Remove pivot bolt.
(12) Remove generator.

Fig. 1 GENERATOR 2.7L

Fig. 2 GENERATOR 3.2L/3.5L

8F - 20

CHARGING

GENERATOR (Continued)

Content .. 68 69 70 71 ..