Mitsubishi Evolution X. Manual - part 888

REAR AXLE DIAGNOSIS <AYC>

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REAR AXLE

27-13

Code No. C161A AYC direction valve (RH) output error

S-AWC-ECU

DIRECTION
VALVE (LH)

DIRECTION
VALVE (RH)

PROPORTIONING
VALVE

FOR AYC
CONTROL

AC708205

Proportioning valve system/direction valve system circuit

Wire colour code
B: Black  LG: Light green  G: Green  L: Blue  W: White  Y: Yellow  SB: Sky blue  BR: Brown  O: Orange  GR: Gray
R: Red  P: Pink  V: Violet  PU: Purple  SI: Silver

AB

C-46

D-11

F-11

F-12

F-10

F-17

F-11

AC708196

AC708214

Connector: C-46

AB

AC706034 AB

Connector: D-11

AC706035 AC

F-11

Connector: F-11, F-12
Body earth: No.9

F-12(B)

No.9

REAR AXLE DIAGNOSIS <AYC>

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CAUTION

If there is any problem in the CAN bus lines, an 
incorrect diagnostic trouble code may be set. 
Prior to this diagnosis, diagnose the CAN bus 
lines.

.

OPERATION

• The power from AWC-ECU is supplied to and 

energizes the hydraulic unit AYC direction valve 
(RH) solenoid.

.

FUNCTION

• The AWC-ECU controls the activation command 

of the coil for the hydraulic unit AYC direction 
valve (RH) solenoid.

• The hydraulic unit AYC direction valve (RH) sole-

noid controls the hydraulic pressure to the AYC 
differential right clutch.

.

TROUBLE JUDGMENT

Range of check

• The DTC related to the power supply circuit is not 

set.

JUDGMENT CRITERIA

• The activation command of the AYC direction 

valve (RH) solenoid is different from that shown 
on the monitor.

Fail-safe, backup function

• The AWC-ECU suspends the AYC control and 

illuminates the multi-information display. Then 
DTC No. C161A is set.

.

PROBABLE CAUSES

• Malfunction inside the AYC direction valve (RH) 

solenoid

• Damaged harness wires and connectors

• Open circuit, short to ground, and connector 

continuity failure between AWC-ECU and 
AYC direction valve (RH) solenoid

• Open circuit and connector continuity failure 

between the AYC direction valve (RH) sole-
noid and the body ground

• Malfunction inside the AWC-ECU

DIAGNOSTIC PROCEDURE

STEP 1. Scan tool CAN bus diagnostics
Using the scan tool, diagnose the CAN bus lines.
Q: Is the check result normal?

YES : Go to Step 3.
NO :  Repair the CAN bus line (Refer to GROUP 54C 

− 

Troubleshooting 

P.54C-14

). After repairing the CAN 

bus line, go to Step 2.

REAR AXLE DIAGNOSIS <AYC>

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STEP 2. DTC recheck after repairing the CAN bus line
(1) Erase the DTC.
(2) Turn the ignition switch from the LOCK (OFF) position to the 

ON position, and then wait for 4 seconds.

(3) Using the scan tool, apply the specified current to the AYC 

proportioning valve, and forcibly activate the AYC direction 
valve (RH). (Refer to Actuator Test Table 

P.27-22

.)

(4) Check if the DTC is set.
Q: Is DTC No. C161A set?

YES : Go to Step 3.
NO :  This diagnosis is complete.

STEP 3. Connector check:
Check the connectors below for improper engagement, termi-
nal damage or terminal drawn in the connector case.

• C-46 AWC-ECU connector

• F-12 AYC direction valve (RH) connector

• D-11 intermediate connector, F-11 intermediate connector

• No. 9 body ground

Q: Are the connectors and terminals in good condition?

YES : Go to Step 4.
NO :  Repair the faulty connector(s) or terminal(s). Then go 

to Step 8.

STEP 4. Harness check
(1) Check the wiring harness among C-46 AWC-ECU 

connector (terminal No. 3), D-11 intermediate connector 
(terminal No. 10), F-11 intermediate connector (terminal No. 
2), and F-12 AYC direction valve (RH) connector (terminal 
No. 2) for any problems.

(2) Check the wiring harness among F-12 AYC direction valve 

(RH) connector (terminal No. 1), F-11 intermediate 
connector (terminal No. 3), and No. 9 body ground for any 
problems.

Q: Is the harness in good condition?

YES : Go to Step 5.
NO :  Repair the problem in the wiring harness. Then go to 

Step 8.

STEP 5. Resistance measurement between AYC direction 
valve solenoid (RH) connector (equipment side) terminals

AC705248AC

F-12(B)Harness connector:
valve side

Hydraulic unit
assembly

Direction valve (RH)

Disconnect the F-12 AYC direction valve (RH) connector and 
measure the resistance between connector terminals on the 
equipment side.

Standard value: 15.9 

± 0.5 Ω

Q: Is the measured resistance value within the standard 

value range?
YES : Go to Step 6.
NO :  Replace the hydraulic unit. (Refer to 

P.27-58

.) Then 

go to Step 8.

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STEP 6. Scan tool service data
Check the following service data. (Refer to 

P.27-22

.)

• Item 95: AYC direction valve (RH) activation command

Q: Is the check result normal?

YES : Go to Step 7.
NO :  Replace the AWC-ECU (Refer to 

P.22A-132

). Then 

go to Step 8.

STEP 7. Check whether the DTC is reset.
(1) Erase the DTC.
(2) Turn the ignition switch from the LOCK (OFF) position to the 

ON position, and then wait for 4 seconds.

(3) Using the scan tool, apply the specified current to the AYC 

proportioning valve, and forcibly activate the AYC direction 
valve (RH). (Refer to Actuator Test Table 

P.27-22

.)

(4) Check if the DTC is set.
Q: Is DTC No. C161A set?

YES : Replace the AWC-ECU (Refer to 

P.22A-132

). Then 

go to Step 8.

NO :  An intermittent malfunction is suspected. (Refer to 

GROUP 00 

− How to Cope with Intermittent 

Malfunction 

P.00-15

.)

STEP 8. Check whether the DTC is reset.
(1) Erase the DTC.
(2) Turn the ignition switch from the LOCK (OFF) position to the 

ON position, and then wait for 4 seconds.

(3) Using the scan tool, apply the specified current to the AYC 

proportioning valve, and forcibly activate the AYC direction 
valve (RH). (Refer to Actuator Test Table 

P.27-22

.)

(4) Check if the DTC is set.
Q: Is DTC No. C161A set?

YES : Diagnose again from Step 1.
NO :  This diagnosis is complete.