Mitsubishi Evolution X. Manual — part 889

REAR AXLE DIAGNOSIS <AYC>

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REAR AXLE

27-17

Code No. C161B AYC direction valve (LH) 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 AD

F-10(B)

F-11

Connector: F-10, F-11
Body earth: No.9

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
(LH) solenoid.

.

FUNCTION

• The AWC-ECU controls the activation command

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

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

noid controls the hydraulic pressure to the AYC
differential left 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 (LH) 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. C161B is set.

.

PROBABLE CAUSES

• Malfunction inside the AYC direction valve (LH)

solenoid

• Damaged harness wires and connectors

• Open circuit, short to ground, and connector

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

• Open circuit and connector continuity failure

between the AYC direction valve (LH) 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 (LH). (Refer to Actuator Test Table

P.27-22

.)

(4) Check if the DTC is set.
Q: Is DTC No. C161B 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-10 AYC direction valve connector (LH)

• 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. 14), D-11 intermediate connector
(terminal No. 22), F-11 intermediate connector (terminal No.
1), and F-10 AYC direction valve (LH) connector (terminal
No. 2) for any problems.

(2) Check the wiring harness among F-10 AYC direction valve

(LH) 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.

REAR AXLE DIAGNOSIS <AYC>

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

AC705248 AD

F-10(B)Harness connector:
valve side

Hydraulic unit
assembly

Direction valve (LH)

Disconnect the F-10 AYC direction valve (LH) 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.

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

P.27-22

.)

• Item 94: AYC direction valve (LH) 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 (LH). (Refer to Actuator Test Table

P.27-22

.)

(4) Check if the DTC is set.
Q: Is DTC No. C161B 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 (LH). (Refer to Actuator Test Table

P.27-22

.)

(4) Check if the DTC is set.
Q: Is DTC No. C161B set?

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