Mitsubishi LANCER EVOLUTION-IV 1998 Workshop Manual page 373

4. INSPECTION PROCEDURES FOR DIAGNOSIS CODES
Code No. 12: Power supply voltage (valve power supply)
system
This code is output when the AYC-ECU power supply voltage drops below, goes
beyond, a specified level.
NOTE
Refer to the corresponding item if any other diagnosis code is being output.
Is the battery voltage correct?
OK
Measure at B-96 AYC-ECU connector.
D Disconnect the connector and
measure at the harness side.
D Ignition switch: ON
D Voltage across 31 and body ground
OK: Battery voltage
OK
Replace AYC-ECU.
Code No. 21, 22, 23, 24: Wheel speed sensor system
This code is output if any one of three wheel speed sensors fails to provide an input
even after the other wheel exceeded 8 km/h.
<Vehicles with ABS>
Is an ABS diagnosis code No. 21, 22,
23, or 24 output?
NO
Measure at B-95 AYC-ECU connector.
D Disconnect the connector and
measure at the harness side.
D Ignition switch: ON
D Turn tire at 1/2 to 1 revolution/sec.
D Voltage across 6/7/8/9 and body
ground
OK: 42 mV or more (when mea-
sured with a circuit tester)
120 mV-P or more (when
measured with an oscillo-
scope)
NG
Check the following connectors:
B-24, B-95
OK
Check the trouble symptom.
NG
Check harness between AYC-ECU
and ABS-ECU.
OK
Replace ABS-ECU.
REAR AXLE –
Troubleshooting <AYC>
NG
Replace
NG
Check the following connectors:
B-96, B-94, B-49, B-75, B-76
Check the trouble symptom.
Check and repair harness between
ignition switch (IG
YES
Troubleshooting
OK
Check the following connector:
B-95
Check the trouble symptom.
Replace AYC-ECU.
NG
Repair
NG
Repair
Probable cause
D Defective harness or connector
D Defective battery
D Defective AYC-ECU
NG
OK
NG
) and AYC-ECU.
2
Probable cause
D Defective harness or connector
D Defective ABS-ECU
D Defective AYC-ECU
NG
OK
OK
Repair
Repair
27-7