1999 MITSUBISHI LANCER EVOLUTION VI check oil

REAR AXLE – Troubleshooting 27-18
Code No. 82: Electric pump systemProbable cause
This code is output if the pressure switch is not set to high-pressure position despite
the AYC-ECU’s command to drive the AYC relay for a given period of time.
Low hydraulic oil level

Oil leak

Defective fusible link

Defective AYC relay

Defective harness or connector

Defective AYC motor

Defective accumulator pressure switch

Defective AYC-ECU
OK
Replace AYC-ECU.
Check the harness
between AYC relay and
AYC motor, and between
AYC motor and body
ground.NG
Replace
NG
OK
Check the trouble symptom.
OK
Check the following
connectors:
A-126, B-94, B-27, F-32NG
Repair
OK
Replace AYC-ECU.
NG
Check the harness
between AYC-ECU and
accumulator pressure
switch.NG
Repair
NG
Check and repair the har-
ness between fusible link
no. 10 and AYC relay.
OK
Check the trouble symp-
tom.
OK
Replace the hydraulic unit
for a defective accumula-
tor pressure switch.
NO
Repair the leak.
OK
Check the trouble symptom.
NG
Check the following
connector: A-126NG
Repair
YES
Add hydraulic oil.
Is the hydraulic oil level correct in the reservoir tank?
(Refer to P.27-33.)NOIs there a hydraulic oil leak?
Measure at A-126 AYC relay connector.

Disconnect the connector and measure at the harness side.

Voltage across 5 and body ground
OK: System voltage
NG
NO
MUT-II Actuator test:
No. 12 Electric pump operation check
OK: Pump operation sounds are heardOKMeasure at F-31 accumulator pressure switch connector.

Disconnect the connector and measure at the harness side.

Ignition switch: ON

Voltage across 2 and body ground
OK:System voltage
YES
Is diagnosis code no. 81 output?YESCheck the AYC relay system. (Refer to P.27-17.)
NG
Check the following
connectors: B-95, B-94,
D-06, F-30, F-31NG
Repair
OK

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

Check AYC motor for
operation.NG
Repair

REAR AXLE – Troubleshooting 27-23
INSPECTION PROCEDURE 4
AYC warning lamp remains lit up after the engine has
started.
Probable cause
The AYC warning lamp ON circuit is probably short-circuited.
Defective combination meter

Defective harness (short-circuit)

Defective AYC-ECU
NOTE
This symptom is limited only when the communication with MUT-II is possible with AYC-ECU power supply
in normal condition and the diagnosis code is correct.
OK
Replace combination meter.
NO
Check the harness between AYC
warning lamp and AYC-ECU.NG
Repair
Does the AYC warning lamp goes out
when the B-96 AYC-ECU connector
is disconnected?YESReplace AYC-ECU.
INSPECTION PROCEDURE 5
AYC is inoperative.
Unable to start or accelerate on slippery road surfaces.
Probable cause
The hydraulic oil level is probably low, there is an oil leak, the hydraulic unit is defective,
or the torque transfer differential is defective.
Low hydraulic oil level

Oil leak

Defective hydraulic unit

Defective torque transfer differential
NOTE
This symptom is limited only when the diagnosis code is correct.
NG
Replace the hydraulic unit.
NG
Replace the torque transfer differential.
Check the trouble symptom.
NG
Replace AYC fluid.
OK
Correct
Check the trouble symptom.NO
Replace the torque transfer differential.
OK
Is foreign matter trapped in the hydrau-
lic line?YES
Repair
OK
Check the AYC for operation.
(Refer to P.27-34.)OKCheck the AYC fluid.
NG
Add hydraulic oil.
NG
Check hydraulic pressure..
(Refer to P.27-35.)NGBleed the system of air.
(Refer to P.27-34.)
Check the hydraulic oil level.NGCheck for oil leak.OK
Repair

REAR AXLE – Troubleshooting 27-27
ACTUATOR TEST REFERENCE TABLE
The following items can be tested by driving the corresponding actuator forcibly using the MUT-II.
Item No.Check itemChecking requirementsNormal value
10Air bleedingSupply current to proportioning
valve in accordance with steering
angle to operate directional valve.No air is to be bled from the
bleeder plug on the torque transfer
differential.
11Oil level checkLet the directional valve operate to
left and right 20 times.To be checked by oil level in
reservoir tank.
12Electric pump operationLet the electric pump operate for 5
seconds.Operation sounds of the electric
pump are to be heard.
13Clutch operation (left)Let the directional valve operate to
supply the maximum pressure to the
left clutch.The operation conditions are to be
checked by the speed difference
between left and right rear wheels
with the wheels raised. For details,
refer to AYC Operation Check on
P.27-34.
14Clutch operation (right)Let the directional valve operate to
supply the maximum pressure to the
right clutch.The operation conditions are to be
checked by the speed difference
between left and right rear wheels
with the wheels raised. For details,
refer to AYC Operation Check on
P.27-34.
15Control OFFTurn off the electric pump relay to
deactivate AYC control.During the test run, some
differences are to be recognized in
running behaviors between when
the system is ON and when it is
OFF.
NOTE
(1) The actuator test is feasible only when the following requirements are all satisfied.

All of inputs from four wheel speed sensors show 20 km/h or lower.

No system failure is registered.

The steering angle is within ±30 deg. from the neutral position.
(2) The actuator test comes to an end when either of the following conditions is met since the forced
actuation is canceled.

Either of inputs from four wheel sensors shows higher than 20 km/h (with exception of Item
No.15 “Control OFF”).

Some trouble with the system is registered.

Forced activation time expires.

MUT-II is removed.

The clear key of MUT-II is operated.

REAR AXLE – On-vehicle Service 27-31
ON-VEHICLE SERVICE

REAR AXLE TOTAL BACKLASH CHECK
If the drive system roars or the vehicle vibrates, use the
following procedure to measure total backlash in the rear
axle. Based on the measurement taken, determine whether
the differential carrier assembly needs to be removed or not.
1. Place the shift lever in the neutral position and operate
the parking brake.
2. Turn the propeller shaft fully clockwise and make an
alignment mark on the companion flange dust cover and
gear carrier.
3. Turn the propeller shaft fully counterclockwise and
measure the deviation between the alignment marks.
Limit: 5 mm
4. If the backlash exceeds the limit, replace the differential
carrier assembly.
GEAR OIL LEVEL CHECK
DIFFERENTIAL
1. Remove the filler plug.
2. Check that the gear oil level is within the specified range
from the bottom end of the filler plug hole.
Standard value (A): 6 mm
3. If the gear oil level exceeds the standard value, add the
specified gear oil up to the bottom end of the filler plug
hole.
Specified gear oil:
Hypoid gear oil API classification GL-5 or higher
SAE viscosity Number 90, 80W.
NOTE
10C or more: #90, less than 10C: #80
4. Fit the filler plug and tighten it to the specified torque.
Alignment marks
Filler plug
49 Nm
Gear oil
Upper
limit
Lower
limit

REAR AXLE – On-vehicle Service 27-32
TORQUE TRANSFER MECHANISM
1. Remove the filler plug.
2. Check that the gear oil level is up to the bottom end
of the filler plug hole.
3. If the gear oil level is lower than the bottom end of the
filler plug hole, add the specified gear oil up to the bottom
end of the filler plug hole.
Specified gear oil:
MITSUBISHI GENUINE DIA QUEEN SUPER AYC
FLUID
4. Fit the filler plug and tighten it to the specified torque.
GEAR OIL CHANGE
DIFFERENTIAL
1. Remove the drain plug to discharge the gear oil.
2. Fit the drain plug and tighten it to the specified torque.
Tightening torque: 49 Nm
3. Remove the filler plug and add the specified gear oil
up to the bottom end of the filler plug hole.
Specified gear oil:
Hypoid gear oil API classification GL-5 or higher
SAE viscosity Number 90, 80W.
Quantity used: 0.41 ± 0.02

NOTE
10C or more: #90, less than 10C: #80
4. Fit the filler plug and tighten it to the specified torque.
Filler plug
49 Nm
Gear oil
Filler plug
49 Nm
Gear oil
Drain plug

REAR AXLE – On-vehicle Service 27-33
TORQUE TRANSFER MECHANISM
1. Remove the drain plug to discharge the gear oil.
2. Fit the drain plug and tighten it to the specified torque.
3. Remove the filler plug.
4. Pour the specified gear oil up to the bottom end of the
filler plug hole using an oil syringe (recommended tool)
through the gap between the body and the differential
support arm.
Specified gear oil:
MITSUBISHI GENUINE DIA QUEEN SUPER AYC
FLUID
Quantity used: 0.70
0
0.05

5. Fit the filler plug and tighten it to the specified torque.
FLUID LEVEL CHECK
1. Remove the maintenance lid located in the luggage
compartment.
2.
If the vehicle has been run, leave it for 5 min. or more
in an ordinary temperature (10C to 30C) to allow the
accumulator internal pressure to drop.
NOTE
If the ambient temperature is less than 10C or less,
allow more time to leave the vehicle to stand idle.

Connect the MUT-II to the 16-pin diagnosis connector.
Turn on the ignition switch. Operate the MUT-II (Item
No.11) to activate the hydraulic unit forcibly for removing
the pressure from inside the accumulator.
Caution
Before connecting or disconnecting the MUT-II,
always turn off the ignition switch.
NOTE
(1) The forced activation (oil level check mode) will be
automatically canceled as soon as the directional
valve in the hydraulic unit is activated to the left and
right 20 times.
It can also be canceled forcibly by operating the clear
key on the MUT-II.
(2) While this function is being disabled by the fail-safe
function, the forced activation of the hydraulic unit
can not be executed.
3. Check that the fluid level in the oil reservoir is in the
range between MAX and MIN.
4. If the fluid level is lower than MIN, add the specified
fluid.
Specified fluid: Dia Queen ATF SP II or equivalent
5. Reinstall the maintenance lid.
Gear oil
Drain plug
49 Nm
Oil syringe
(Recommended tool)
Filler plug
49 Nm

REAR AXLE – On-vehicle Service REAR AXLE – On-vehicle Service 27-34
BLEEDING
1. Lift up the vehicle.
2. Connect the MUT-II to the 16-pin diagnosis connector.
Caution
Before connecting or disconnecting the MUT-II,
always turn off the ignition switch.
3. Turn on the ignition switch.
4. Operate the MUT-II (Item No.10) to activate the hydraulic
unit forcibly.
NOTE
(1) The forced activation (air bleeding mode) will be
automatically canceled after 5 minutes operation. It
can also be canceled forcibly by operating the clear
key on the MUT-II.
(2) While this function is being disabled by the fail-safe
function, the forced activation of the hydraulic unit
can not be executed.
5. Remove the cap of the left bleeder screw on the torque
transfer differential and connect a vinyl hose.
6. Gradually turn the steering wheel clockwise from the
straight-ahead position. At this time, loosen the left bleeder
screw and check that fluid is discharged with air.
7. After air has been completely discharged, tighten the
bleeder screw.
Caution
While the system is being bled of air, add fluid as
necessary to ensure that it is left in the oil reservoir
during the entire procedure.
8. Repeat steps (6) and (7) two to three times until no air
bubbles are recognized in the fluid that comes out. Then,
tighten the bleeder screw to the specified torque.
Tightening torque: 9 Nm
9. Perform steps (5) through (8) for the right bleeder screw.
Note, however, that the steering wheel should be turned
counterclockwise.
10. After the system has been completely bled of air, check
for the fluid level. (Refer to P.27-33.)
Caution
If the system is not completely bled of air, the hydraulic
unit could generate noise, degrading pump durability.
AYC OPERATION CHECK
1. Lift up the vehicle.
2. Connect the MUT-II to the 16-pin diagnosis connector.
Caution
Before connecting or disconnecting the MUT-II, always
turn off the ignition switch.
3. Start the engine.
4. Operate the MUT-II with the transmission in 2nd or a
higher gear and check to ensure that the vehicle speed
is higher than 10 km/h using the Data List (Item 10).
Bleeder
screws Vinyl hose

REAR AXLE – On-vehicle Service 27-36
(2) While this function is being disabled by the fail-safe
function, the forced activation of the hydraulic unit
can not be executed.
6. Check to ensure that the hydraulic pressure generated
by the hydraulic unit conforms to the standard value.
Standard value: 1.0 – 1.6 MPa
NOTE
During checking the hydraulic pressure, occasionally
replenish the oil reservoir with fluid so that it does not
become empty.
7. Check the hydraulic pressure of the clutch right side by
repeating the steps (4) through (6). At this time, however,
the special tool must be connected to the R port and
the blind plug or the R port of the removed hydraulic
unit hose assembly must be attached to the L port. Further,
the MUT-II must be operated in the forced activation mode
Item No. 14 (clutch right side operation check mode).
8. If the measured value exceeds the standard value, replace
the hydraulic unit.
9. Connect the hydraulic unit hose assembly to the hydraulic
unit and to the torque transfer differential and tighten
the flare nuts to the specified torque.
Specified torque: 34 Nm
10. Pour the specified fluid in the oil reservoir up to the MAX
mark. Then, bleed the system.
Specified fluid: Dia Queen ATF SP II or equivalent
Fluid amount used: Approx. 1

DIFFERENTIAL CARRIER OIL SEAL
REPLACEMENT
DIFFERENTIAL
1. Remove the drive shaft.
2. Remove the oil seal from the differential carrier.
3. Using the special tool, drive a new oil seal all the way
into position.
4. Coat the oil seal lips and the drive shaft surface in contact
with the oil seal with multi-purpose grease.
5. Replace the drive shaft circlip with a new one and mount
the drive shaft to the differential carrier.
6. Check for correct wheel alignment.
TORQUE TRANSFER MECHANISM
1. Remove the drive shaft.
2. Remove the oil seal from the differential carrier.
3. Using the special tool, drive a new oil seal all the way
into position.
4. Coat the oil seal lips and the drive shaft surface in contact
with the oil seal with the specified grease.
Specified grease: Vaseline
5. Replace the drive shaft circlip with a new one and mount
the drive shaft to the differential carrier.
6. Check for correct wheel alignment.
MB990938
MB991115
MD998829
MD998812
MD998813