Mitsubishi Lancer Evolution VI. Manual - part 55

REAR AXLE – 

Troubleshooting <AYC>

27-14

Code No. 65: ABS monitor system

Probable cause

This code is output when ABS is considered to remain activated (motor relay remains
ON) for a continuous 1-min.-or-more period.
It is output also when there is an open-circuit in the harness between ABS motor
relay and AYC-ECU.

D

Defective harness or connector

D

Defective AYC-ECU

OK

Replace AYC-ECU.

NG

Check the harness between ABS
motor relay and AYC-ECU.

NG

Repair

OK

Check the trouble symptom.

Is the ABS diagnosis code output?

YES

Refer to Group 35B – Troubleshooting

NO

Check the following connector:
B-95

NG

Repair

Code No. 71: Proportioning valve system

Probable cause

This code is output when the proportioning valve control circuit is open- or short-circuited.

D

Defective proportioning valve

D

Defective harness or connector

D

Defective AYC-ECU

OK

Check and repair the harness between
proportioning valve and body ground.

OK

Check the trouble symptom.

OK

Measure at F-27 proportioning valve
connector.

D

Disconnect the connector and
measure at the harness side.

D

Continuity across 2 and body
ground
OK: Conducting

NG

Check the following connectors:
F-27, F-30

NG

Repair

Measure at F-27 proportioning valve
connector.

D

Disconnect the connector and
measure at the proportioning valve.

D

Resistance across 2 –  3
OK: 4.7 

Ω

 or less

NG

Replace the hydraulic unit.

OK

Replace AYC-ECU.

NG

Check the harness between propor-
tioning valve and AYC-ECU.

NG

Repair

OK

Check the trouble symptom.

OK

Check the following connectors:
B-96, B-94, D-06, F-30, F-27

NG

Repair

REAR AXLE – 

Troubleshooting <AYC>

27-15

Code No. 72: Directional control valve (right) system

Probable cause

This code is output when the directional control valve (right) control circuit is open-
or short-circuited.

D

Defective directional control valve (right)

D

Defective harness or connector

D

Defective AYC-ECU

OK

Check and repair the harness between
directional control valve (right) and
body ground.

OK

Check the trouble symptom.

OK

Replace AYC-ECU.

NG

Check the harness between directional
control valve (right) and AYC-ECU.

NG

Repair

OK

Check the trouble symptom.

OK

Check the following connectors:
B-96, B-94, D-06, F-30, F-29

NG

Repair

OK

Measure at F-29 directional control
valve (right) connector.

D

Disconnect the connector and
measure at the directional control
valve side.

D

Continuity across 1 and body
ground
OK: Conducting

NG

Check the following connectors:
F-29, F-30

NG

Repair

Measure at F-29 directional control
valve (right) connector.

D

Disconnect the connector and
measure at the directional control
valve side.

D

Resistance across 1 –  2
OK: 19  – 21 

Ω

 or less

NG

Replace the hydraulic unit.

REAR AXLE – 

Troubleshooting <AYC>

27-16

Code No. 73: Directional control valve (left) system

Probable cause

This code is output when the directional control valve  (left) control circuit is open-
or short-circuited.

D

Defective directional control valve (left)

D

Defective harness or connector

D

Defective AYC-ECU

NG

Check and repair the harness between
directional control valve (left) and body
ground.

OK

Check the trouble symptom.

OK

Replace AYC-ECU.

NG

Check the harness between directional
control valve (left) and AYC-ECU.

NG

Repair

OK

Check the trouble symptom.

OK

Check the following connectors:
B-96, B-94, D-06, F-30, F-28

NG

Repair

OK

Measure at F-28 directional control
valve (left) connector.

D

Disconnect the connector and
measure at the directional control
valve side.

D

Continuity across 1 and body
ground
OK: Conducting

NG

Check the following connectors:
F-28, F-30

NG

Repair

Measure at F-28 directional control
valve (left) connector.

D

Disconnect the connector and
measure at the directional control
valve side.

D

Resistance across 1 –  2
OK: 19  – 21 

Ω

 or less

NG

Replace the hydraulic unit.

REAR AXLE – 

Troubleshooting <AYC>

27-17

Code No. 81: AYC relay system

Probable cause

This code is output when the coil circuit of the AYC relay is open- or short-circuited.

D

Defective AYC relay

D

Defective harness or connector

D

Defective AYC-ECU

NG

Check and repair the harness between
AYC relay and body ground.

OK

Check the trouble symptom.

OK

Replace AYC-ECU.

NG

Check the harness between AYC relay
and AYC-ECU.

NG

Repair

NG

Check the trouble symptom.

OK

Check the following connectors:
B-96, B-126

NG

Repair

OK

Measure at A-126 AYC relay connec-
tor.

D

Disconnect the connector and
measure at the harness side.

D

Continuity across 1 and body
ground
OK: Conducting

NG

Check the following connector:
A-126

NG

Repair

Check the AYC relay. 
(Refer to P.27-42.)

NG

Replace the AYC relay.