Rotation of the excited field coil generates AC voltage
in the stator.
This alternating current is rectified through diodes to
DC voltage having a waveform shown in the
illustration above.

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 current
increases and it falls as the field current decreases.
When  the  battery  positive  voltage  (generator  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.

ZK600346

Generator

Stator
coil

ECM

G
S
L
FR

Voltage
regulator

Battery

Field coil

AA00

Generator
malfunction light

CAN communication

GENERAL SPECIFICATIONS

M11601000002USA0000010000

Item

Specification

Type

Positive battery positive voltage sensing

Identification number

A3TG4491

16a-2

CHARGING SYSTEM

GENERAL INFORMATION

Item

Specification

Part No.

1800A141

Rated output V/A

12/120

Voltage regulator

Electronic built-in type

SERVICE SPECIFICATIONS

M11601000003USA0000010000

Item

Standard value

Limit

Regulated voltage
(Ambient temperature at
voltage regulator)

-20°C (-4°F)

14.2 - 15.4

20°C (68°F)

13.9 - 14.9

60°C (140°F)

13.4 - 14.6

80°C (176°F)

13.1 - 14.5

Generator output line voltage drop (at 30 A) V

Maximum 0.3

Output current

70 % of normal output
current

Field coil resistance Ω

Approximately 2 - 5

Brush protrusion length mm (in)

Minimum 2 (0.08)

CHARGING SYSTEM DIAGNOSIS

M11601000007USA0000010000

TROUBLESHOOTING HINTS

Generator malfunction light dose not go on when the ignition
switch is turned to ON, before the engine starts.

｠

Check the bulb.

Generator malfunction 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 generator malfunction 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
following steps.
STEP 1.

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

Chassis Electrical - Battery - On-vehicle Service - Battery

Check P.54Aa-2.)

YES:

Go to Step 2.

NO:

Charge or replace the battery.

CHARGING SYSTEM

16a-3

SERVICE SPECIFICATIONS

STEP 2.

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

GROUP 00, General - Maintenance Service - Drive Belts

(For Generator and Air Conditioning) (Check) P.00-58.)

YES:

Go to Step 3.

NO:

Adjust the belt tension or replace the belt.

STEP 3.

Q:Does the generator malfunction light come on 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.
54Ag-15).

｠

Check for burnt-out generator malfunction light.

｠

Check the generator malfunction light-related circuits.

STEP 4.

Q:Does the generator malfunction light go out after starting

the engine?

YES:

Go to Step 5.

NO:

Check the generator malfunction light-related

circuits.

STEP 5.

Q:Is an oscilloscope available?

YES:

Go to Step 6.

NO:

Go to Step 7.

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.16a-11.)

YES:

Go to Step 7.

NO:

Check the generator related circuit. If the circuit

is normal, replace the generator (Refer to Charging
System - Generator Assembly - Generator Assembly Removal
and Instllation P.16a-13).

STEP 7.

｠

Engine: 2,500 r/min

｠

Headlight: ON (high beam)

｠

Voltage between generator terminal B and the positive battery
terminal
OK: 0.5 V or less

｠

Voltage between the negative battery terminal and generator
body
OK: 0.5 V or less

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

condition?

YES:

Go to Step 8.

16a-4

CHARGING SYSTEM

CHARGING SYSTEM DIAGNOSIS

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