Mitsubishi Evolution X. Manual — part 890

REAR AXLE DIAGNOSIS <AYC>

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REAR AXLE

27-21

Code No. C1620 AYC control abnormality

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 proportioning
valve and direction valve (RH/LH) solenoid.

.

FUNCTION

• The AWC-ECU controls the specified current of

the coil for the hydraulic unit AYC proportioning
valve solenoid, and activation command of the
coil for the AYC direction valve (RH/LH) solenoid.

• The hydraulic unit AYC proportioning valve and

direction valve (RH/LH) solenoid control the
hydraulic pressure to the AYC differential right/left
clutch.

.

TROUBLE JUDGMENT

Range of check

• The forced activation of actuator is not underway.

• The output to the AYC proportioning valve sole-

noid is 0.05 A or more.

JUDGMENT CRITERIA

• Due to the AYC differential clutch protection, DTC

No. C161F is set.

• The AYC proportioning valve solenoid is ener-

gized longer than the specified duration.

Fail-safe, backup function

• The AWC-ECU suspends the AYC control and

illuminates the multi-information display. Then
DTC No. C1620 is set.

.

PROBABLE CAUSES

• The driving and road conditions are severe.

• Malfunction inside the AWC-ECU

DIAGNOSTIC PROCEDURE

STEP 1. CAN bus diagnostics using the scan tool
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.

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.

(3) Check if the DTC is set.

Q: Is DTC No. C1620 set?

YES :

Go to Step 3.

NO :

This diagnosis is complete.

STEP 3. Check whether the DTC is reset.
(1) Erase the DTC.
(2) Turn the ignition switch from the LOCK (OFF)

position to the ON position.

(3) Check if the DTC is set.

Q: Is DTC No. C1620 set?

YES :

Replace the AWC-ECU (refer to

P.22A-132

), and check that another DTC is

not set. Then go to Step 4.

NO :

This diagnosis is complete. Under the
driving and road conditions where the AYC
control is operated long time (e.g.: long time
cornering), the clutch protection is operated.

STEP 4. Check whether the DTC is reset.
(1) Erase the DTC.
(2) Turn the ignition switch from the LOCK (OFF)

position to the ON position.

Q: Is DTC No. C1620 set?

YES :

Diagnose again from Step 1.

NO :

This diagnosis is complete.

REAR AXLE DIAGNOSIS <AYC>

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REAR AXLE

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TROUBLE SYMPTOM CHART

M1271004300366

CAUTION

During diagnosis, a DTC associated with other system may be set when the ignition switch is turned
ON with connector(s) disconnected. On completion, confirm all systems for diagnostic trouble
code(s). If diagnostic trouble code(s) are set, erase them all.
NOTE: For trouble symptom not mentioned, refer to the GROUP 22A

−

Symptom Chart

P.22A-14

.

Symptom

Inspection
procedure

Reference pages or
actions

Noise from the AYC differential during cornering

1

P.27-22

INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS

Inspection Procedure 1: Abnormal noise from AYC differential (torque transfer mechanism) during
cornering

.

COMMENTS ON TROUBLE SYMPTOM

If the abnormal noise form AYC differential is heard
during corning under the system operation, AYC dif-
ferential may have a problem.

.

PROBABLE CAUSES

• AYC differential gear oil failure (low oil level, oil

contamination)

• Malfunction of AYC differential

DIAGNOSTIC PROCEDURE

STEP 1. AYC differential gear oil level check
Check the AYC differential torque transfer mecha-
nism for gear oil level and oil contamination. (Refer
to

P.27-28

.)

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Fill the specified gear oil up to the gear oil
level for the torque transfer mechanism, and
replace if the contamination is severe.
(Refer to

P.27-29

.) Then, go to Step 3.

STEP 2. Check of AYC reoperation
Using the scan tool, check the AYC operation under
forced activation. (Refer to

P.27-31

.)

Q: Does a malfunction take place again?

YES :

Replace the AYC differential. (Refer to

P.27-52

.) Then, go to Step 3.

NO :

This diagnosis is complete.

STEP 3. Check of AYC reoperation
Using the scan tool, check the AYC operation under
forced activation. (Refer to

P.27-31

.)

Q: Does a malfunction take place again?

YES :

Diagnose again from Step 1.

NO :

This diagnosis is complete.

DATA LIST REFERENCE TABLE

M1271006900018

Refer to GROUP 22A

− Data List Reference Table

P.22A-107

Contents.

ACTUATOR TEST REFERENCE TABLE

M1271007000018

Refer to GROUP 22A

− Actuator Test Reference

Table

P.22A-113

Contents.

CHECK AT AWC-ECU

M1271007200012

Refer to GROUP 22A

− Check at AWC-ECU Termi-

nal Voltage

P.22A-114

Contents.

SPECIAL TOOL

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REAR AXLE

27-23

SPECIAL TOOL

M1271000600990

Tool

Tool number and
name

Supersession

Application

MB991910

MB991826

MB991955

MB991911

MB991824

MB991827

MB991825

a

b

c

d

e

f

DO NOT USE

MB991955

a: MB991824
b: MB991827
c: MB991910
d: MB991911
e: MB991825
f: MB991826

M.U.T.-III Sub
Assembly

a: Vehicle

communication
interface (V.C.I.)

b: M.U.T.-III USB

Cable

c: M.U.T.-III Main

Harness A
(Vehicles with
CAN
communication
system)

d: M.U.T.-III Main

Harness B
(Vehicles without
CAN
communication
system)

e: M.U.T.-III main

harness C (for
Daimler Chrysler
models only)

f: M.U.T.-III Adapter

Harness

g: M.U.T.-III Trigger

Harness

MB991824-KIT
NOTE: G: MB991826
M.U.T.-III Trigger
Harness is not
necessary when
pushing V.C.I.
ENTER key.

CAUTION

For vehicles with CAN
communication, use M.U.T.-III main
harness A to send simulated
vehicle speed. If you connect
M.U.T.-III main harness B instead,
the CAN communication does not
function correctly.
Checking the AYC (Diagnosis display,
service data display and calibration
by using the scan tool)

MD998330
Oil pressure gauge

−

Hydraulic pressure measurement

MB991705

MB991705
Hose adapter

−

MB991551

SPECIAL TOOL

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REAR AXLE

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MB991551
Bearing outer race
installer

−

Press-fitting of the oil seal (AYC
differential mechanism part: use
together with MB990938)

MB991245

MB991245
Lower arm bush ring

−

Press-fitting of the oil seal (AYC
differential torque transfer
mechanism part)

B990767

MB990767
Front hub and flange
yoke holder

MB990767-01

Hub fixing

MB991618

MB991618
Hub bolt remover

General service tool

Removal of the hub bolt

MB990241AD

B

A

MB990241

A:MB990242
B:MB990244

Axle shaft puller

A: Puller shaft
B: Puller bar

MB990241-01 or
General service tool

• Removal of the drive shaft

• Removal of the rear hub assembly

MB991354

MB991354
Puller body

General service tool

MB990211

MB990211
Slide hammer

General service tool

Rear hub assembly removal

A

B

C

MB991017

A:MB991017
B:MB990998
C:MB991000

A, B: Front hub

remover and
installer

C: Spacer

MB990998-01

• Provisional holding of the wheel

bearing

• Hub rotation starting torque

measurement

• Measurement of wheel bearing

end play
NOTE: MB991000, which belongs
to MB990998, should be used as a
spacer.

Tool

Tool number and
name

Supersession

Application