Mitsubishi MOTORS Space Runner 1999 Workshop Manual Supplement page 374

Code No.12 Air flow sensor system
Range of check
Engine speed is 500 r/min or more.
Set conditions
Sensor output frequency is 3.3 Hz or less for 4 seconds.
Measure at the air flow sensor connec-
tor A-73.
Connect the connector
(Use the test harness MB991709)
(1) Voltage between 3 and earth
(Engine: Idling)
OK: 2.2 – 3.2 V
(2) Voltage between 7 and earth
OK: 0 – 0.1 V
(Engine: Idling)
OK: 6 – 9 V
(Engine speed: 4,000 r/min)
OK
Replace the engine-ECU.
GDI –
Troubleshooting
(1) NG
Measure at the air flow sensor connec-
tor A-73.
Disconnect the connector, and
measure at the harness side.
(1) Voltage between 4 and earth
(Ignition switch: ON)
OK: System voltage
(2) Voltage between 3 and earth
(2) NG
(Ignition switch: ON)
OK: 4.8 – 5.2 V
(3) Continuity between 5 and earth
OK: Continuity
OK
Check the following connector:
A-73
OK
Check trouble symptom.
NG
Replace the air flow sensor.
Measure at the engine-ECU connector
B-28.
Connect the connector
Voltage between 19 and earth
(Ignition switch: ON)
OK: 6 – 9 V
OK
Check the following connector:
B-28
OK
NG
Check trouble symptom.
Probable cause
Malfunction of the air flow sensor
Open circuit or short-circuited harness wire of air
flow sensor circuit
Malfunction of the engine-ECU
(1) NG
Check the harness wire between the
air flow sensor and the engine control
relay, and repair if necessary.
(2), (3) NG
Check the following connector:
B-31
Check trouble symptom.
Check the harness wire between the
engine-ECU and the air flow sensor,
and repair if necessary.
NG
Repair
Replace the engine-ECU.
NG
Check the following connector:
A-73
Check trouble symptom.
Replace the air flow sensor.
NG
Repair
13A-15
OK
NG
Repair
NG
OK
NG
Repair
OK
NG
Repair
NG