Page 71 of 788
CHARGING SYSTEM
ENGINE ELECTRICAL16-7
REGULATED VOLTAGE TESTM1161001100354
This test determines whether the voltage regulator
correctly controlling the alternator output voltage.
1. Always be sure to check the following before the
test.
•Alternator installation
•Check that the battery installed in the vehicle is
fully charged.
(Refer to GROUP 54A − Battery − On-vehicle
Service − Charging P.54A-4).
•Drive belt tension
(Refer to GROUP 11A − On-vehicle Service <4G1>
P.11A-7 or GROUP 11C − On-vehicle Service
<4G6> P.11C-7.)
•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 test harness
(MB991519) to connect a digital voltmeter
between the alternator "S" terminal and earth
[Connect the (+) lead of the voltmeter to the "S"
terminal, and then connect the (-) lead of the
voltmeter to a secure earth or to the battery (-)
terminal].
5. Connect a clamp-type DC test ammeter with a
range of 0 − 120 A to the alternator "B" terminal
output wire.NOTE: The way of disconnecting the alternator
output wire and of connecting the ammeter is
possibly not found the problem that the output
current is dropping due to the insufficient
connection between terminal "B" and the output
wire.
6. Reconnect the negative battery cable.
7. Connect a tachometer or the MUT-II/III (Refer to
GROUP 11A − On-vehicle Service − Idle speed
check <4G1> P.11A-11 or GROUP 11C −
On-vehicle Service − Idle speed check <4G6>
P.11C-11).
8. Turn the ignition switch to the "ON" position and
check that the reading on the voltmeter is equal to
the battery 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 (+)
terminal.
9. Turn all lamps and accessories off.
10.Start the engine.
11.Increase the engine speed to 2,500 r/min.
12.Read the value displayed on the voltmeter when
the alternator output current alternator becomes
10 A or less.
13.If the voltage reading conforms to the value in the
voltage regulation, then the voltage regulator is
operating normally.
AK300727AB
BatteryIgnition switch
Engine-ECU
Engine-A/T-ECU Ammeter (clamp-type)Load
Black MB991519
Voltmeter (digital-type) Red
YellowBlueAlternator B
FR
L
S
G
Page 72 of 788
CHARGING SYSTEM
ENGINE ELECTRICAL16-8
If the voltage is not within the standard value,
there is a malfunction of the voltage regulator or of
the alternator.
14.After the test, lower the engine speed to the idle
speed.
15.Turn the ignition switch to the "LOCK" (OFF)
position.
16.Remove the tachometer or the MUT-II/III.17.Disconnect the negative battery cable.
18.Disconnect the ammeter and voltmeter.
19.Connect the alternator output wire to the
alternator "B" terminal.
20.Remove the special tool, and return the connector
to the original condition.
21.Connect the negative battery cable.
Voltage Regulation Table
Standard value:
Inspection terminal Voltage regulator ambient
temperature °CVoltage V
Terminal "S"
−2014.2 − 15.4
20 13.9 − 14.9
60 13.4 − 14.6
80 13.1 − 14.5
Page 73 of 788
CHARGING SYSTEM
ENGINE ELECTRICAL16-9
WAVEFORM CHECK USING AN OSCILLOSCOPEM1161001200124
MEASUREMENT METHODConnect the oscilloscope special patterns pick-up to
the alternator "B" terminal.
STANDARD WAVEFORM
Observation Conditions
NOTE:
The voltage waveform of the alternator "B" terminal
can undulate as shown in the illustration. This
waveform is produced when the regulator operates
according to fluctuations in the alternator load (current), and is normal for the alternator. In addition,
when the voltage waveform reaches an excessively
high value (approximately 2 V or higher at idle), it
often indicates an open circuit due to a brown fuse
between alternator "B" terminal and battery, but not a
defective alternator.
AK100002
Alternator
"B" terminalCH1
AC
Function Special pattern
Pattern height Variable
Variable knob Adjust while viewing the waveform.
Pattern selector Raster
Engine speed Curb idle speed
AKX00189
0.4 (V)
0.2
0
–0.2
–0.4 Voltage at
alternator
"B" terminal
Time
AG
AKX00190
Page 74 of 788
CHARGING SYSTEM
ENGINE ELECTRICAL16-10
EXAMPLE OF ABNORMAL WAVEFORMS
NOTE: .
1. The size of the waveform patterns differs largely, depending on the adjustment of the variable knob on the
oscilloscope.
2. Identification of abnormal waveforms is easier when there is a large output current (regulator is not
operating). (Waveforms can be observed when the headlamps are illuminated.)
3. Check the conditions of the charging warning lamp (illuminated/not illuminated). Also, check the charging
system totally.
Abnormal waveform Problem cause
Example 1 Open diode
Example 2 Short in diode
AKX00191
AKX00192
Page 75 of 788
CHARGING SYSTEM
ENGINE ELECTRICAL16-11
Example 3 Broken wire in
stator coil
Example 4 Short in stator
coil
Example 5
At this time, the charging warning lamp is illuminated.Open
supplementary
diode Abnormal waveform Problem cause
AKX00193
AKX00194
AKX00195
Page 76 of 788
Page 77 of 788
CHARGING SYSTEM
ENGINE ELECTRICAL16-13
REMOVAL AND INSTALLATION <4G6>M1161001400559
Pre-removal Operation
•Under Cover Removal
•Strut Tower Bar Removal (Refer to GROUP 42 P.42-9).
•Drive Belt Removal (Refer to GROUP 11C - Crankshaft
Pulley P.11C-16).
•Air Cleaner Assembly Removal (Refer to GROUP 15
P.15-3).Post-installation Operation
•Air Cleaner Assembly Installation (Refer to GROUP 15
P.15-3).
•Drive Belt Installation (Refer to GROUP 11C - Crankshaft
Pulley P.11C-16).
•Strut Tower Bar Installation (Refer to GROUP 42 P.42-9).
•Drive Belt Tension Adjustment (Refer to GROUP 11C -
On-vehicle Service P.11C-7).
•Under Cover Installation
AC303826
1
2
318 ± 3 N·m
AB
Removal steps
1. Shift cable connection<>2. shift cable and shift cable bracket
assembly
3. Vehicle speed sensor connectorRemoval steps (Continued)
Page 78 of 788
