2005 MITSUBISHI 380 Workshop Manual

CHARGING SYSTEM
ENGINE ELECTRICAL16-8
10.With the engine running at 2,500 r/min, turn the
headlights and other lights on and off to adjust the
alternator load so that the value displayed on the
ammeter is slightly above 30 A.
Read the voltmeter. Voltage reading at or below
limit value means voltage drop between alternator
and battery is OK.
Limit value: maximum 0.3 V
NOTE: When the alternator 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 decreasing
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 alternator output wire. Check the wiring
between the alternator "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 engine tachometer or diagnostic
tool.
15.Disconnect the negative battery cable.
16.Disconnect the ammeter and voltmeter.
17.Connect the negative battery cable.
18.Run the engine for 10 minutes at an idle.
OUTPUT CURRENT TESTM1161001000670

CHARGING SYSTEM
ENGINE ELECTRICAL16-9
Required Special Tool:
: Diagnostic Tool (MUT-III)
MB991824: V.C.I.
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
This test determines whether the alternator outputs
normal current. For best results, use a charging sys-
tem tester. If not available, follow the steps below.
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.
Alternator installation
Battery (Refer to GROUP 54A, Chassis Electrical
Battery On-vehicle Service Battery Check
P.54A-5.)
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.
Alternator drive belt tension (Refer to GROUP 00,
General
Maintenance Service Drive Belts
(For Alternator, Power Steering Pump and Air
Conditioning) (Check) P.00-39.)
Fusible link
Abnormal noise from the alternator while the
engine is running.
2. Turn the ignition switch to the "LOCK" (OFF)
position.
3. Disconnect the negative battery cable.
Never use clips to connect the wire. Loose
connections (for example, using clips) will
lead to a serious accident because of high
current.
4. Connect a clamp-type DC test ammeter with a
range of 0
120 A to the alternator "B" terminal
output wire.
5. Connect a voltmeter with a range of 0
20 V
between the alternator "B" terminal and ground.
(Connect the positive lead of the voltmeter to the
"B" terminal, and then connect the negative lead
of the voltmeter to ground.)
6. Connect the negative battery cable.
7. Connect an engine tachometer or diagnostic tool.
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 alternator "B" terminal and the battery positive
terminal or malfunctioning voltmeter.
10.After turning on the headlights, start the engine.
NOTE: Because the current from the battery will
soon drop after the engine is started, step 11
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
highest 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
Alternator Specifications.
NOTE: The current output value will depend on
the electrical load and the temperature of the
alternator body.
NOTE: If the electrical load is small while testing,
the specified level of current may not be output
even though the alternator is normal. In such
cases, increase the electrical load by leaving the
headlights turned on for some time to discharge
the battery or by using the lighting system in
another vehicle, and then test again.
NOTE: The specified level of current also may not
be output if the temperature of the alternator body
or the ambient temperature is too high. In such
cases, cool the alternator 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 alternator output wire is normal, remove
the alternator from the engine and check the
alternator.
13.Run the engine at idle speed after the test.
14.Turn the ignition switch to the "LOCK" (OFF)
position.
15.Disconnect the engine tachometer or diagnostic
tool.
16.Disconnect the negative battery cable.
17.Disconnect the ammeter and voltmeter .
18.Connect the negative battery cable.
19.Run the engine for 10 minutes at an idle.

CHARGING SYSTEM
ENGINE ELECTRICAL16-10
REGULATED VOLTAGE TESTM1161001100666
Required Special Tools:
: Diagnostic Tool (MUT-III)
MB991824: V.C.I.
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
MB998467: Alternator Harness Connector
This test determines whether the voltage regulator is
correctly controlling the alternator output voltage.
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:
Alternator installation
Check to be sure that the battery installed in the
vehicle is fully charged. (Refer to GROUP 54A,
Chassis Electrical
Battery On-vehicle Service
Battery Check P.54A-5.)
Alternator drive belt tension (Refer to GROUP 00,
General
Maintenance Service Drive Belts
(For Alternator, Power Steering Pump and Air
Conditioning) (Check) P.00-39.)
Fusible link
Abnormal noise from the alternator while the
engine is running.2. Turn the ignition switch to the "LOCK" (OFF)
position.
3. Disconnect the negative battery cable.
4. Use the special tool (Alternator harness
connector: MB998467) to connect a digital-type
voltmeter between the alternator "S" terminal and
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 negative battery terminal.)
5. Connect a clamp-type DC test ammeter with a
range of 0
120 A to the alternator "B" terminal
output wire.
6. Reconnect the negative battery cable.
7. Connect an engine tachometer, or diagnostic tool.
8. 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 alternator "S" terminal and the battery positive
terminal or malfunctioning voltmeter.
9. Check to be sure that all lights and accessories
are off.
10.Start the engine.

CHARGING SYSTEM
ENGINE ELECTRICAL16-11
11.Increase the engine speed to 2,500 r/min.
12.Read the value displayed on the voltmeter when
the current output by the alternator becomes 10 A
or less.
13.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
alternator (Refer to the following table).14.After the test, lower the engine speed to idle.
15.Turn the ignition switch to the "LOCK" (OFF)
position.
16.Disconnect the engine tachometer or diagnostic
tool .
17.Disconnect the negative battery cable.
18.Disconnect the ammeter and voltmeter.
19.Connect the negative battery cable.
20.Run the engine for 10 minutes at an idle.
VOLTAGE REGULATION TABLE
WAVE PATTERN CHECK USING AN
OSCILLOSCOPE
M1161001200180.
MEASUREMENT METHOD
Connect the oscilloscope special patterns pick-up to the
alternator "B" terminal.
.
STANDARD WAVEFORM
INSPECTION TERMINAL VOLTAGE REGULATOR
AMBIENT TEMPERATURE [
C
(
F)]STANDARD VALUE (V)
Te r m i n a l " S "
20 (4)14.2 15.4
20 (68) 13.9
14.9
60 (140) 13.4
14.5
80 (176) 13.1
14.2
Observation Conditions
FUNCTION SPECIAL PATTERNS
Pattern height Variable
Variable knob Adjust while viewing the wave
pattern
Pattern selector Raster
Engine revolutions Curb idle speed

CHARGING SYSTEM
ENGINE ELECTRICAL16-12
NOTE: The voltage waveform of the alternator "B" terminal can
undulate as shown at left. This waveform is produced when the
regulator operates according to fluctuations in the alternator
load (current), and is normal for the alternator.
If the ripple height is abnormally high (approximately 2 V or
more during idling), the wires between the alternator "B" termi-
nal and the battery have broken due to fuse blowing, etc. The
alternator is usually operating properly.
.
ABNORMAL WAVEFORMS EXAMPLES
NOTE: The size of the waveform patterns can differ greatly,
depending on the adjustment of the variable knob on the oscil-
loscope.
NOTE: Identification of abnormal waveforms is easier when
there is a large output current (regulator is not operating).
(Waveforms can be observed when the headlights are illumi-
nated.)
NOTE: Check the conditions of the alternator malfunction light
(illuminated/not illuminated) also, and carry out a total check.
ABNORMAL WAVEFORMS
Example 1
PROBABLE CAUSE: Open circuit in diode

CHARGING SYSTEM
ENGINE ELECTRICAL16-13
Example 2
PROBABLE CAUSE: Short-circuit in diode
Example 3
PROBABLE CAUSE: Open circuit in stator coil
Example 4
PROBABLE CAUSE: Short-circuit in stator coil

CHARGING SYSTEM
ENGINE ELECTRICAL16-14
ALTERNATOR ASSEMBLY
REMOVAL AND INSTALLATION M1161001400601
REMOVAL SERVICE POINT
.
<> A/C COMPRESSOR ASSEMBLY REMOVAL
Remove the compressor from the compressor bracket with the
hose still attached.
Pre-removal and Post-installation Operation
Under Cover Removal and Installation (Refer to GROUP
51, Under Cover P.51-13).
Side Under Cover Removal and Installation (Refer to
GROUP 51, Under Cover P.51-13).
REMOVAL STEPS
1.
ALTERNATOR DRIVE BELT
2.
ALTERNATOR CONNECTOR3. A/C COMPRESSOR ASSEMBLY
CONNECTOR
<>4. A/C COMPRESSOR ASSEMBLY
<>5.
ALTERNATOR ASSEMBLY REMOVAL STEPS (Continued)