Mitsubishi Montero (2002-2004). Manual — part 1083

CHARGING SYSTEM

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ENGINE ELECTRICAL

16-5

SPECIAL TOOL

M1161000600022

ON-VEHICLE SERVICE

GENERATOR OUTPUT LINE VOLTAGE DROP TEST

M1161000900175

Required Special Tool:
MB991502: Scan Tool
This test determines whether the wiring from the
generator "B" terminal to the positive battery terminal
(including the fusible link) is in good condition or not:

WARNING

Battery posts, terminals and related acces-
sories contain lead and lead compounds.
WASH HANDS AFTER HANDLING.

1. Always be sure to check the following before the

test.

• Generator installation

• Generator drive belt tension (Refer to GROUP

00, Maintenance Service

− Drive belts

P.00-39

.)

• Fusible link

• Abnormal noise from the generator while the

engine is running

2. Turn the ignition switch to the "OFF" position.

3. Disconnect the negative battery cable.
4. Disconnect the generator output wire from the

generator "B" terminal and connect a DC test
ammeter with a range of 0

− 100 A in series

between the "B" terminal and the disconnected
output wire. (Connect the positive lead of the
ammeter to the "B" terminal, and then connect the
negative lead of the ammeter to the disconnected
output wire.)
NOTE: A clamp-type ammeter which enables
measurements to be taken without disconnecting
the generator output wire is recommended. If the
voltage may have dropped due to a bad connec-
tion at generator "B" and the generator "B" termi-
nal is loosened when the test ammeter is
connected, the connection will be completed at
this time and the possibility of finding problems
will be reduced.

TOOL

TOOL NUMBER AND
NAME

SUPERSESSION

APPLICATION

MB991502
Scan tool (MUT-II)

MB991496-OD

Checking of engine idle
speed

B991502

AKX00185

GENERATOR

AMMETER

VOLTMETER
(DIGITAL-TYPE)

BATTERY

+

–

"B"TERMINAL

AB

CHARGING SYSTEM

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ENGINE ELECTRICAL

16-6

5. Connect a digital-type voltmeter between the

generator "B" terminal and the positive battery
terminal. (Connect the positive lead of the
voltmeter to the "B" terminal, and then connect the
negative lead of the voltmeter to the positive
battery cable.)

6. Reconnect the negative battery cable.
7. Connect a tachometer or scan tool MB991502.
8. Leave the hood open.
9. Start the engine.
10.With the engine running at 2,500 r/min, turn the

headlights and other lights on and off to adjust the
generator load so that the value displayed on the
ammeter is slightly above 30 A.

Limit value: maximum 0.3 V

NOTE: When the generator output is high and the
value displayed on the ammeter does not
decrease to 30 A, set the value to 40 A. Read the
value displayed on the voltmeter at this time.
In this case the limit value becomes maximum 0.4
V. Adjust the engine speed by gradually decreas-
ing it until the value displayed on the ammeter is
30 A. Take a reading of the value displayed on the
voltmeter at this time.

11.If the value displayed on the voltmeter is above

the limit value, there is probably a malfunction in
the generator output wire, Check the wiring
between the generator "B" terminal and the
positive battery terminal (including fusible link). If
a terminal is not sufficiently tight or if the harness
has become discolored due to overheating, repair
and then test again.

12.After the test, run the engine at idle.
13.Turn off all lights and turn the ignition switch to the

"LOCK" (OFF) position.

14.Disconnect the tachometer or scan tool

MB991502.

15.Disconnect the negative battery cable.
16.Disconnect the ammeter and voltmeter and

tachometer.

17.Connect the generator output wire to the

generator "B" terminal.

18.Connect the negative battery cable.

OUTPUT CURRENT TEST

M1161001000164

Required Special Tool:
MB991502: Scan Tool (MUT-II)
This test determines whether the generator outputs

normal current.

WARNING

Battery posts, terminals and related acces-
sories contain lead and lead compounds.
WASH HANDS AFTER HANDLING.

1. Before the test, always be sure to check the

following.

AKX00186

GENERATOR

AMMETER

VOLTMETER

BATTERY

+

-

IGNITION
SWITCH

CHARGING INDICATOR

BRAKE WARNING LIGHT

L

S

B

LOAD

AB

CHARGING SYSTEM

TSB Revision

ENGINE ELECTRICAL

16-7

• Generator installation

• Battery (Refer to GROUP 54A, Battery − On-

vehicle Service

− Battery Check

P.54A-4

.)

NOTE: The battery to be used should be slightly
discharged. The load in a fully-charged battery
will be insufficient and the test may not be able to
be carried out correctly.

• Generator drive belt tension (Refer to GROUP

00, Maintenance Service

− Drive Belts

P.00-39

.)

• Fusible link

• Abnormal noise from the generator while the

engine is running

2. Turn the ignition switch to the "LOCK" (OFF)

position.

3. Disconnect the negative battery cable.

WARNING

Never use clips to connect the line. Loose
connections (e.g. using clips) will lead to a
serious accident because of high current.

4. Disconnect the generator output wire from the

generator "B" terminal and connect a DC test
ammeter with a range of 0

− 100 A in series

between the "B" terminal and the disconnected
output wire. (Connect the positive lead of the
ammeter to the "B" terminal, and then connect the
negative lead of the ammeter to the disconnected
output wire.)
NOTE: A clamp-type ammeter which enables
measurements to be taken without disconnecting
the generator output wire is recommended.

5. Connect a voltmeter with a range of 0

− 20 V

between the generator "B" terminal and the
ground. (Connect the positive lead of the
voltmeter to the "B" terminal, and then connect the
negative lead of the voltmeter to the ground.)

6. Connect the negative battery cable.
7. Connect a tachometer or scan tool MB991502.
8. Leave the hood open.
9. Check to be sure that the reading on the voltmeter

is equal to the battery positive voltage.
NOTE: If the voltage is 0 V, the cause is probably
an open circuit in the wire or fusible link between
the generator "B" terminal and the battery positive
terminal.

10.After turning the light switch on and turning on the

headlights, start the engine.
NOTE: Because the current from the battery will
soon drop after the engine is started, step11
should be carried out as quickly as possible in
order to obtain the maximum current output value.

11.Immediately after setting the headlights to high

beam and turning the heater blower switch to the
high revolution position, increase the engine
speed to 2,500 r/min and read the maximum
current output value displayed on the ammeter.

Limit value: 70 % of nominal current output

NOTE: For the nominal current output, refer to the
Generator Specifications
NOTE: The current output value will depend on
the electrical load and the temperature of the gen-
erator body.
NOTE: If the electrical load is small while testing,
the specified level of current may not be output
even though the generator is normal. In such
cases, increase the electrical load by leaving the
headlights turned on for some time to discharge
the battery.
NOTE: The specified level of current also may not
be output if the temperature of the generator body
or the ambient temperature is too high. In such
cases, cool the generator and then test again.

12.The reading on the ammeter should be above the

limit value. If the reading is below the limit value
and the generator output wire is normal, remove
the generator from the engine and check the
generator.

13.Run the engine at idle speed after the test.
14.Turn the ignition switch to the "LOCK" (OFF)

position.

15.Disconnect the tachometer or scan tool

MB991502.

16.Disconnect the negative battery cable.
17.Disconnect the ammeter and voltmeter and

tachometer.

18.Connect the generator output wire to the

generator "B" terminal.

19.Connect the negative battery cable.

CHARGING SYSTEM

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ENGINE ELECTRICAL

16-8

REGULATED VOLTAGE TEST

M1161001100172

Required Special Tool:
MB991502: Scan Tool (MUT-II)
This test determines whether the voltage regulator is
correctly controlling the generator output voltage.

WARNING

Battery posts, terminals and related acces-
sories contain lead and lead compounds.
WASH HANDS AFTER HANDLING.

1. Always be sure to check the following before the

test:

• Generator installation

• Check to be sure that the battery installed in the

vehicle is fully charged (Refer to GROUP 54A,
Battery

− On-vehicle Service − Battery Check

P.54A-4

.)

• Generator drive belt tension (Refer to GROUP

00, Maintenance Service

− Drive Belts

P.00-39

.)

• Fusible link

• Abnormal noise from the generator while the

engine is running

2. Turn the ignition switch to the "LOCK" (OFF)

position.

3. Disconnect the negative battery cable.
4. Connect a digital-type voltmeter between the

generator "S" terminal and the ground. (Connect
the positive lead of the voltmeter to the "S"
terminal, and then connect the negative lead of
the voltmeter to a secure ground or to the battery
negative terminal.)

5. Disconnect the generator output wire from the

generator "B" terminal.

6. Connect a DC test ammeter with a range of 0

−

100 A in series between the "B" terminal and the
disconnected output wire. (Connect the positive
load of the ammeter to the "B" terminal, and then
connect the negative lead of the ammeter to the
disconnected output wire.)

7. Reconnect the negative battery cable.
8. Connect a tachometer or the scan tool

MB991502.

9. Turn the ignition switch to the "ON" position and

check that the reading on the voltmeter is equal to
the battery positive voltage.
NOTE: If the voltage is 0 V, the cause is probably
an open circuit in the wire or fusible link between
the generator "S" terminal and the battery positive
terminal.

10.Check to be sure that all lights and accessories

are off.

11.Start the engine.
12.Increase the engine speed to 2,500 r/min.
13.Read the value displayed on the voltmeter when

the current output by the generator becomes 10 A
or less.

14.If the voltage reading conforms to the value in the

voltage regulation table, then the voltage regulator
is operating normally.
If the voltage is outside the standard value, there
is a malfunction of the voltage regulator or the
generator (Refer to the following table).

AKX00187

IGNITION
SWITCH(IG1) CHARGING INDICATOR

BRAKE WARNING LIGHT

GENERATOR

AMMETER

VOLTMETER
(DIGITAL-TYPE)

LOAD

L

S

B

BATTERY

+

-

AB