Mitsubishi Lancer Evolution IV, Workshop Manual

Page: 193 / 391

REAR AXLE – Troubleshooting <AYC>
27-10
Code No. 26: Wheel speed sensor system (faulty output
signal) Probable cause
This code is output if the speed of one of the four wheels exceeds a specified level
when the vehicle speed is 20 km/h or more. At this time, the warning lamp is turned
on.
D
Defective harness or connector
D
Defective AYC-ECU
D
Defective ABS-ECU
<Vehicles with ABS>
OK
Replace ABS-ECU.
NG
Check harness between AYC-ECU
and ABS-ECU.
NG
Repair
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
NG
Check the following connectors:
B-24, B-95
NG
Repair
OK
Check the trouble symptom.
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 connector:
B-95
Is ABS diagnosis code No. 15 output?
YES
Troubleshooting
NG
Repair
<Vehicles without ABS>
NG
Check and repair the harness between
speed sensor and AYC-ECU.
OK
Check the trouble symptom.
OK
Check the following connectors:
B-95, B-52, B-17, A-26, A-50, D-04,
D-14, D-19
NG
Repair
OK
Check wheel bearing.
NG
Replace
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
OK
Check the following connector:
B-95
NG
Repair
OK
Check speed sensor output voltage.
(Refer to P.27-31.)
NG
Check speed sensor and rotor.
Check speed sensor for installation.
NG
Repair
NG
Replace