Subaru XT 1988 Service Manual page 1209

6-1 ENGINE ELECTRICAL SYSTEM
TROUBLESHOOTING (ON THE CAR)
AL TERNATOR (2700 cc model)
1. Rotational speed refers to the number of engine revolutions.
2. General inspections such as belt tightness and connector contact should be completed before troubleshooting.
3. Replace the battery with a good one for accurate inspection.
BATTERY OVER-DISCHARGES
*1
IC alternator terminal-B voltage (at 2,000 rpm) is
YES After idling 2 or 3 minutes (more than S minutes
higher than during idling
when battery discharges), increase speed to 2,SOO
rpm and check terminal-L voltage to see if it is
NO
regulation voltage (14.0 to lS.0V)
I
Check IC alternator terminal-L voltage when
1 to 3V YES
t
NO
ignition switch is ON and engine stops
IC alternator defective
Battery voltage
*2
Disassemble and check
o
to lV
(10 to 12V)
Check IC regulator
O.S to 2V
terminal-F voltage
'--
with ignition switch ON
Check IC alternator terminal-L voltage with IC
and engine stopped
alternator terminals Band IG shortcircuited with
1 to 3V Battery
voltage
another lead wire
(10 to 12V)
Faulty contact
Replace
o
to lV
of wiring on positive
body side (+) diode
NO
Disconnect IC alternator connector and check for
Replace IC regulatorl
continuity in the direction from IG to L
o
to O_SV
YES
I
Field coil broken
Faulty brush contact
I
I
NO
I
Ground terminal-L
I
Terminal-L grounded?
I
OK
Disconnect wiring from IC alternator terminal B
I Replace I C regulator
1
63A or less
and connect ammeter (SOA, min.). After starting
t engine, increase speed to 2,SOO to 3,000 rpm and
I
IC alternator defective
I
read maximum amperage with all electrical loads
turned ON
63 to 81A
I
81A or more
~
81A or more
After discharging battery slightly,
I
Normal
I
carry out previous operation
~
81Aorless
Check IC alternator
* 1, *2: See next page.
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