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 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-

CHARGING

8F - 21

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.

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

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

Diagnostic manual 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)

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

8F - 22

CHARGING

CHARGING (Continued)

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:

Type

Engine

Minimun Test
Amperage

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

Bolt

14.7

180

Generator B+ Nut

12.4

9.2

110

Battery Terminal Nut

Generator Mounting Bolt

2.4L

28.2

20.8

250

Generator Mounting Bolts

3.3/3.8L

54.2

Starter Solenoid Battery

Nut 3.3/3.8L

11.3

8.3

100

Generator Decoupler

109.8

SPECIFICATIONS - BATTERY TEMPERATURE SENSOR

°C

°F

K-Ohms Min.

K-Ohms Max.

(40)

291.4

381.7

(20)

(4)

85.8

108.4

11.4

13.6

9.1

10.9

120

248

0.37

0.41

130

266

0.28

0.32

CHARGING

8F - 23

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

For vehicles with 1.6L engine, there is no physical

battery temp sensor in place to detect battery temp.
Rather, an algorithm buit in PCM is employed to pre-
dict battery temp using inlet air temp, vehicle speed,
and coolant temp, among other signals. 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 — 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 20°F.

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:

• Worn, loose or defective bearings

• Loose or defective drive pulley (2.4L) or decou-

pler (3.3/3.8L)

• Incorrect, worn, damaged or misadjusted drive

belt

• Loose mounting bolts

• Misaligned drive pulley

• Defective stator or diode

• Damaged 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.

GENERATOR DECOUPLER 8433

8F - 24

CHARGING

CHARGING (Continued)

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