Mitsubishi MOTORS Space Runner 1999 Workshop Manual Supplement page 420

INSPECTION PROCEDURE 19
Low alternator output voltage (approx. 12.3 V)
The cause is probably a malfunction of the alternator or one of the problems
listed at right.
Measure at the alternator connector
A-93.
Connect the connector. (Use the
test harness MB991519)
Voltage between 1 (black clip)
and earth
(Engine: Idling)
(Radiator fan: Not operating)
(Headlamp: OFF ON)
(Stop lamp: OFF ON)
(Rear defogger switch: OFF
ON)
OK: Voltage increases by 0.2 –
3.5 V.
OK
Check the alternator. (Refer to GROUP
16 – Charging System.)
INSPECTION PROCEDURE 20
Idling speed is improper when A/C is operating
If the engine-ECU detects that the air conditioner is on, it activates the idle speed
control (ISC) servo to control idle-up operation.
The A/C-ECU judges if the load caused by air conditioner operation is high or low,
and converts it to voltage signal (high or low voltage) and inputs the signal to the
engine-ECU.
Based on this voltage signal, the engine-ECU controls the idle-up speed (for high
or low load).
Measure at the engine-ECU connector B-31.
Connect the connector.
Voltage between 73 and earth (Engine: at idle, outside air
temperature: 25_C or more)
OK: 0 – 3 V [When A/C is MAX. COOL condition (when
the load by A/C is high)]
System voltage [When A/C is MAX. HOT condition (when
the load by A/C is low)]
Check the A/C system. (Refer to GROUP 55 – On-vehicle Service.)
GDI –
NG
Measure at the alternator connector
A-93.
Disconnect the connector, and
measure at the harness side.
Disconnect the engine-ECU
connector.
Continuity between 1 and earth
OK: No continuity
OK
Check the following connectors:
A-75, B-29
OK
Replace the engine-ECU.
NG
Troubleshooting
Probable cause
Malfunction of the charging system
Open circuit between the alternator G terminal
and the engine-ECU
Malfunction of the engine-ECU
NG
NG
Repair
Probable cause
Malfunction of the A/C control system
Improper
short-circuited harness wire
Malfunction of the engine-ECU
OK
Check the following connector:
B-16, B-19
OK
Check trouble symptom.
NG
Replace the engine-ECU.
13A-61
Check the harness wire between
the alternator and the engine-ECU,
and repair if necessary.
connector contact, open circuit
NG
Repair
or