Mitsubishi Eclipse. Manual — part 665

CHARGING SYSTEM

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ENGINE ELECTRICAL

16-3

CHARGING SYSTEM

GENERAL DESCRIPTION

M1161000100328

The charging system charges the battery with the
generator output to keep the battery charged at a
constant level during varying electrical load.

OPERATION

Rotation of the excited field coil generates AC volt-
age in the stator.
This alternating current is rectified through diodes to
DC voltage having a waveform shown in the illustra-
tion at left.
The average output voltage fluctuates slightly with
the generator load condition.

When the ignition switch is turned on, current flows in
the field coil and initial excitation of the field coil
occurs.
When the stator coil begins to generate power after
the engine is started, the field coil is excited by the
output current of the stator coil.
The generator output voltage rises as the field cur-
rent increases and it falls as the field current
decreases. When the battery positive voltage (gener-
ator S terminal voltage) reaches a regulated voltage
of approximately 14.4 V, the field current is cut off.
When the battery positive voltage drops below the
regulated voltage, the voltage regulator regulates the
output voltage to a constant level by controlling the
field current.
In addition, when the field current is constant, the
generator output voltage rises as the engine speed
increases.

CHARGING SYSTEM DIAGNOSIS

M1161000700212

TROUBLESHOOTING HINTS

Charging warning light dose not go on when the ignition switch

is turned to ON, before the engine starts.

• Check the bulb.

AKX00183

VOLTAGE

TIME

APPROXIMATELY
14.4 V

AB

AK301527

GENERATOR

<2.4L ENGINE (FEDERAL AND CALIFORNIA - M/T)>

B

STATOR
COIL

CHARGING
WARNING
LIGHT

IGNITION
SWITCH

BATTERY

FIELD COIL

GENERATOR

<2.4L ENGINE (FEDERAL AND CALIFORNIA - A/T, CANADA),
3.0L ENGINE>

B

STATOR
COIL

ECM<M/T>
PCM<A/T>

ECM

CHARGING
WARNING
LIGHT

IGNITION
SWITCH

FIELD COIL

BATTERY

AB

G

S

L

FR

+

+

–

–

VOLTAGE REGULATOR

G

S

L

FR

VOLTAGE REGULATOR

CHARGING SYSTEM

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ENGINE ELECTRICAL

16-4

Charging warning light dose not switch off after the engine

starts.

• Check the IC voltage regulator inside the generator.

Discharged or overcharged battery.

• Check the IC voltage regulator inside the generator.

The charging warning light illuminates dimly.

• Check the diode (inside the combination meter) for a

short-circuit.

TROUBLESHOOTING GUIDE

The charging system troubleshooting guide is shown in the fol-
lowing steps.

STEP 1.
Q: Is the battery in good condition? (Refer to GROUP 54A,

Chassis Electrical

− Battery − On-vehicle Service −

Battery Check

P.54A-5

.)

YES : Go to Step 2.
NO : Charge or replace the battery.

STEP 2.
Q: Is the generator drive belt in good condition? (Refer to

GROUP 00, General

− Maintenance Service − 9. Drive

Belt (For the Generator, Water Pump and Power
Steering Pump) (Check Condition)

P.00-46

.)

YES : Go to Step 3.
NO : Adjust the belt tension or replace the belt.

STEP 3.
Q: Does the charging warning light brightly when the

ignition switch is turned on?
YES : Go to Step 4.
NO :

• Check the ignition switch. (Refer to GROUP 54A,

Chassis Electrical

− Ignition Switch − Ignition

Switch

− Inspection

P.54A-43

.)

• Check for burnt-out charging warning light.

• Check the generator. (Refer to Charging System −

Generator Assembly

− Inspection

P.16-19

.)

• Check the charging warning light-related circuits.

STEP 4.
Q: Does the charging warning light go out after starting the

engine?
YES : Go to Step 5.
NO : Check the generator (Refer to Charging System

−

Generator Assembly

− Inspection

P.16-19

.)

STEP 5.
Q: Is an oscilloscope available?

YES : Go to Step 6.
NO : Go to Step 7.

CHARGING SYSTEM

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ENGINE ELECTRICAL

16-5

STEP 6.
Q: Dose the oscilloscope show a normal wave pattern?

(Refer to Charging System

− On-vehicle Service − Wave

Pattern Check Using an Oscilloscope

P.16-11

.)

YES : Go to Step 7.
NO : Check the generator. (Refer to Charging System

−

Generator Assembly

− Inspection

P.16-19

.)

STEP 7.

• Engine: 2,500 r/min

• Headlight: ON (high beam)

• Voltage between generator terminal B and the positive bat-

tery terminal
OK: 0.5 V or less

• Voltage between the negative battery terminal and genera-

tor body
OK: 0.5 V or less

Q: Are the generator output line and ground line in good

condition?
YES : Go to Step 8.
NO : Check the generator output line and ground line.

STEP 8.
Q: Is the output current normal? (Refer to Charging

System

− On-vehicle Service − Output Current Test

P.16-8

.)

YES : Go to Step 9.
NO : Check the generator (Refer to Charging System

−

Generator Assembly

− Inspection

P.16-19

.)

STEP 9.
Q: Is the regulated voltage normal? (Refer to Charging

System

− On-vehicle Service − Regulated Voltage Test

P.16-10

.)

YES : Go to Step 10.
NO : Check the generator (Refer to Charging System

−

Generator Assembly

− Inspection

P.16-19

.)

STEP 10.
Q: Is the voltage drops in the generator output line

normal?
YES : Generator is normal. Check other systems.
NO : Check the output line.

CHARGING SYSTEM

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ENGINE ELECTRICAL

16-6

SPECIAL TOOL

M1161000600259

TOOL

TOOL NUMBER AND
NAME

SUPERSESSION

APPLICATION

MB991958
A: MB991824
B: MB991827
C: MB991910
D: MB991911
E: MB991914
F: MB991825
G: MB991826
MUT-III sub assembly
A: Vehicle
Communication Interface
(V.C.I.)
B: MUT-III USB Cable
C: MUT-III Main Harness
A (Vehicles with CAN
communication system)
D: MUT-III Main Harness
B (Vehicles without CAN
communication system)
E: MUT-III Main Harness
C (for Chrysler models
only)
F: MUT-III Adapter
Harness
G: MUT-III Trigger
Harness

Tool not available

Checking of engine idle
speed

MB991519
Generator harness
connector

MIT530
Micrd 530 charging
system tester.

Checking of generator
("S" terminal voltage)

MB991910

MB991826

MB991958

MB991911

MB991914

MB991824

MB991827

MB991825

DO NOT USE

A

B

C

D

E

F

G

DO NOT USE