Mitsubishi Lancer Evolution-IV Workshop Manual page 49

13-8
2. INSPECTION CHART FOR DIAGNOSIS CODES
Code No. Diagnosis item
12 Air flow sensor (AFS) system
13 Intake air temperature sensor system
14 Throttle position sensor (TPS) system
21 Engine coolant temperature sensor system
22 Crank angle sensor system
23 Camshaft position sensor system
24 Vehicle speed sensor system
25 Barometric pressure sensor system
31 Detonation sensor system
41 Injector system
44 Ignition coil and power transistor unit system
64 Alternator FR terminal system
3. INSPECTION PROCEDURE FOR DIAGNOSIS CODES
Code No. 12 Air flow sensor (AFS) system
Range of Check
D Engine speed is 500 r/min or more.
Set conditions
D Sensor output frequency is 3 Hz or less for 4 seconds.
Measure at the air flow sensor con-
nector A-25.
D 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 – 1 V (Engine: idling)
6 – 9 V (2,000 r/min)
OK
Replace the engine-ECU.
MPI –
Troubleshooting
1. NG
Check the air flow sensor circuit.
2. NG
Measure at the engine-ECU con-
nector B-59.
D Connect the connector.
D Voltage between 19 and earth
(Ignition switch: ON)
OK: 6 – 9 V
OK
Check the following connector:
B-59
OK
Check trouble symptom.
NG
Replace the engine-ECU.
Probable cause
D Malfunction of the air flow sensor
D Improper
connector
short-circuited harness wire of the air flow sensor
D Malfunction of the engine-ECU
NG
Check the following connector:
A-25
OK
Check trouble symptom.
NG
NG
Repair
Replace the air flow sensor.
Reference page
13-8
13-9
13-9
13-10
13-11
13-11
13-12
13-13
13-14
13-14
13-15
13-16
contact, open circuit or
NG
Repair