1998 MITSUBISHI LANCER EVOLUTION IV wheel

REAR AXLE – Troubleshooting 27-10
Code No. 26: Wheel speed sensor system (faulty output
signal)Probable cause
This code is output if the speed of one of the four wheels exceeds a specified level
when the vehicle speed is 20 km/h or more. At this time, the warning lamp is turned
on.
Defective harness or connector

Defective AYC-ECU

Defective ABS-ECU

OK
Replace ABS-ECU.
NG
Check harness between AYC-ECU
and ABS-ECU.NG
Repair
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
NG
Check the following connectors:
B-24, B-95NG
Repair
OK
Check the trouble symptom.
NO
Measure at B-95 AYC-ECU connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON

Turn tire at 1/2 to 1 revolution/sec.

Voltage across 6/7/8/9 and body
ground.
OK:42 mV or more (when mea-
sured with a circuit tester)
120 mV-P or more (when
measured with an oscillo-
scope)NGCheck the following connector:
B-95
Is ABS diagnosis code No. 15 output?YESTroubleshooting
NG
Repair

NG
Check and repair the harness between
speed sensor and AYC-ECU.
OK
Check the trouble symptom.
OK
Check the following connectors:
B-95, B-52, B-17, A-26, A-50, D-04,
D-14, D-19NG
Repair
OK
Check wheel bearing.NG
Replace
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
OK
Check the following connector:
B-95NG
Repair
OK
Check speed sensor output voltage.
(Refer to P.27-31.)NGCheck speed sensor and rotor.
Check speed sensor for installation.NG
Repair
NG
Replace

REAR AXLE – Troubleshooting 27-11
Code No. 31: Steer sensor (ST-1, ST-2, ST-N) systemProbable cause
This code is output when any of the steer sensors ST-1, ST-2, and ST-N is open-circuited
or the steer sensor ground wire is open-circuited.
Defective steer sensor

Defective harness or connector

Defective AYC-ECU
OK
Replace the steer sensor.
NG
Check the harness between steer sen-
sor and AYC-ECU.NG
Repair
NG
Check and repair the harness between
speed sensor and AYC-ECU.
OK
Check the trouble symptom.
OK
Check the trouble symptom.
OK
Check the following connectors:
B-95, B-65, B-98NG
Repair
NG: Voltage remains
at 4 V or more.
Measure at B-98 steer sensor connec-
tor.

Disconnect the connector and
measure at the harness side.

Continuity across 3 and body
ground
OK:ConductingNGCheck the following connectors:
B-98, B-50NG
Repair
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
Measure at B-95 AYC-ECU connector.

Connector connected.

Ignition switch: ON

Voltage across 4/5/17 and body ground.
OK:The voltage alternates between about
3 V and about 0.5 V when the steering
wheel is turned.OKCheck the following connector:
B-95NG
Repair
NG: Voltage alternates
between 4 V or
more and 0.5 V.NG: Voltage
remains
at 0 V.
Code No. 32: Steer sensor (ST-N) systemProbable cause
This code is output when the steering wheel is considered to be turned 40 or more
as determined with ST-1 and ST-2 with ST-N ON (LOW voltage).
Defective steer sensor

Defective harness or connector

Defective AYC-ECU
OK
Replace the steer sensor.
NG
Check the harness between steer sen-
sor and AYC-ECU.NG
Repair
OK
Replace AYC-ECU.
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
OK
Check the trouble symptom.
NG
Measure at B-95 AYC-ECU connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON

Turn steering wheel about 90 in
either direction from the straight-
ahead position.

Voltage across 17 and body
ground.
OK:No continuityNGCheck the following connectors:
B-95, B-65, B-98NG
Repair
Measure at B-95 AYC-ECU connector.

Connector connected.

Ignition switch: ON

Turn steering wheel about 90 in
either direction from the straight-
ahead position.

Voltage across 17 and body
ground.
OK:The voltage increases from
about 0.5 V or less to about
3.5 V.OKCheck the following connector:
B-95NG
Repair

REAR AXLE – Troubleshooting 27-12
Code No. 33: Steer sensor (ST-N) systemProbable cause
This code is output when the steering wheel is turned 400 or more in the same
direction with ST-N OFF (HIGH voltage).
Defective steer sensor

Defective harness or connector

Defective AYC-ECU
NG
Replace AYC-ECU.
Check the trouble symptom.
OK
Replace the steer sensor.
NG
Check the harness between steer sen-
sor and AYC-ECU.NG
Repair
OK
Replace AYC-ECU.
OK
Check the trouble symptom.
Measure at B-95 AYC-ECU connector.

Connector connected.

Ignition switch: ON

Turn steering wheel about 90 in
either direction from the straight-
ahead position.

Voltage across 17 and body
ground.
OK:The voltage increases from
about 0.5 V or less to about
3.5 V.NGCheck the following connectors:
B-95, B-65, B-98NG
Repair
Code No. 34: Steer sensor (ST-1, ST-2) systemProbable cause
This code is output if a turning condition is detected for a cumulative period of time
of 15 min. or more, during which there is no change in the steer sensor (ST-1, ST-2)
signals with the wheel speed 15 km/h or more.
Defective steer sensor

Defective harness or connector

Defective AYC-ECU
NG
Replace AYC-ECU.
Check the trouble symptom.
OK
Replace the steer sensor.
NG
Check the harness between steer sen-
sor and AYC-ECU.NG
Repair
OK
Replace AYC-ECU.
OK
Check the trouble symptom.
Measure at B-95 AYC-ECU connector.

Connector connected.

Ignition switch: ON

Voltage across 4/5 and body
ground
OK:The voltage alternates
between about 0.5 V and
about 3 V as the steering
wheel is turned.NGCheck the following connectors:
B-95, B-65, B-98NG
Repair

REAR AXLE – Troubleshooting 27-24
7. CHECK AT AYC-ECU TERMINALS
7-1 TERMINAL VOLTAGE LISTING
(1) The voltage is to be measured across each terminal and ground terminal.
(2) Fig. below shows the arrangement of the terminals.
Terminal
No.Check itemCheck requirementNormally
1Lateral acceleration sensorIgnition switch: ON2.4 – 2.6 V
(horizontal position)
2Longitudinal acceleration
sensor ground
Lateral acceleration sensor
groundAt all times0 V
3Longitudinal acceleration
sensorIgnition switch: ON2.4 – 2.6 V
(horizontal position)
4Steer sensor (ST-2)Engine: Idle speed
Turn steering wheel slowly.0 V ↔ approx. 3 V
flashing
5Steer sensor (ST-1)Engine: Idle speed
Turn steering wheel slowly.0 V ↔ approx. 3 V
flashing
6*1FR wheel speedVehicle stationary1 V or less
Forward vehicle slowly.0 – 5 V
7*1FL wheel speedVehicle stationary1 V or less
Forward vehicle slowly.0 – 5 V
8*1RR wheel speedVehicle stationary1 V or less
Forward vehicle slowly.0 – 5 V
9*1FL wheel speedVehicle stationary1 V or less
Forward vehicle slowly.0 – 5 V
10Diagnosis selection inputBattery voltage
11Stop lamp switchIgnition switch:
ON
Stop lamp switch: ONBattery voltage
ON
Stop lamp switch: OFF1 V or less
12*1ABS monitorWhen ABS monitor is activatedBattery voltage
When ABS monitor is deactivated1 V or less
17Steer sensor (ST-N)Engine:
Idle speed
Steering wheel: Neutral position0.5 V or less
Idle speed
Steering wheel: Turned 90 from
neutral position2.5 – 3.5 V

REAR AXLE – On-vehicle Service 27-29
3-2 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 and 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
Quantity used: 0.70
0
0.05dm3{0.700
0.05}
(4) Fit the filler plug and tighten it to the specified torque.
4. 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 (10
C to 30
C) to allow the
accumulator internal pressure to drop.
NOTE
If the ambient temperature is less than 10
C or less,
allow more time to leave the vehicle to stand idle.
(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: MITSUBISHI DIA QUEEN ATF-SPII
(5) Reinstall the maintenance lid.
5. BLEEDING
(1) Lift up the vehicle.
(2) Remove the cap of the left bleeder screw on the torque
transfer differential and connect a vinyl hose.
(3) 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.
(4) 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.
(5) Repeat steps (3) and (4) 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 {0.9 kgf
m}
(6) Perform steps (2) through (5) for the right bleeder screw.
Note, however, that the steering wheel should be turned
counterclockwise.
Filler plug
49 Nm {5.0 kgf
m}
Gear oil
Drain plug
49 Nm
{5.0 kgf
m}
Bleeder
screws Vinyl hose

REAR AXLE – On-vehicle Service 27-30
(7) After the system has been completely bled of air, check
for the fluid level.
Caution
If the system is not completely bled of air, the hydraulic
unit could generate noise, degrading pump durability.
6. DIFFERENTIAL CARRIER OIL SEAL
REPLACEMENT
6-1 DIFFERENTIAL
(1) Remove the drive shaft. (Refer to p. 27-36.)
(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. (Refer to P.27-36.)
(6) Check for correct wheel alignment. (Refer to GROUP
34 – On-vehicle Service.)
6-2 TORQUE TRANSFER MECHANISM
(1) Remove the drive shaft. (Refer to p. 27-36.)
(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. (Refer to P.27-36.)
(6) Check for correct wheel alignment. (Refer to GROUP
34 – On-vehicle Service.)MB990938
MB991115
MD998829
MD998812
MD998813

REAR AXLE – On-vehicle Service 27-31
7. SPEED SENSOR OUTPUT VOLTAGE
MEASUREMENT ABS>
(1) Lift up the vehicle and release the parking brake.
(2) Disconnect the AYC-ECU harness connector and take
measurements on the harness side connector.
Caution
Insert the probe from the harness side with the double
lock of the connector unlocked. Inserting it to the
terminal side could result in poor contact.
(3) Turn the wheel to be tested at about 1/2 to one
revolution/sec. and check for the output voltage using
a circuit tester (AC mV range) or oscilloscope.
Terminal nos.
Front LHFront RHRear LHRear RH
7698
20192221
Output voltage:
When circuit tester is used: 70 mV or more
When oscilloscope is used: 200 mVp-p or more
(4) If the output voltage is lower than the above value, it
is probably attributable to the following faults. Check or
replace the speed sensor as necessary.
Excessive clearance between the pole piece and rotor
of the speed sensor
Defective speed sensor
Waveform Check Using Oscilloscope
Check the harness and connector of the speed sensor for
connection. Then, use an oscilloscope to check for output
voltage waveform of each speed sensor as follows.
Start the engine and monitor the sensor by turning the wheel;
for a driving wheel, let it turn by shifting into the 1st gear
and for a driven wheel turn it manually at a constant speed.
NOTE
(1) Waveform may be observed by actually running the
vehicle.
(2) The output voltage is low when the wheel speed remains
low and builds up as the wheel speed increases.
AYC-ECU connector harness side
When turned manually
At idle (5 to 6 km/h)
1st gear

REAR AXLE – Rear Hub Assembly27-34
INSTALLATION SERVICE POINT
ADRIVE SHAFT NUT INSTALLATION
(1) Install the washer on the drive shaft in the direction shown
on the left.
(2) Using the special tool, tighten the drive shaft nut to the
specified torque.
Caution
Before torquing the drive shaft nut to specification,
do not apply vehicle weight to the wheel bearing.
(3) If, at this time, the split pin holes are not aligned, tighten
the nut further (within 255 Nm {26.0 kgf
m}), insert the
split pin in the first matching holes, and bend it securely.
INSPECTION
1. REAR WHEEL BEARING ROTATION STARTING
TORQUE
(1) Install the special tool to the rear hub assembly and tighten
it to the specified torque.
(2) Using the special tool, measure the wheel bearing rotation
starting torque.
Limit: 1.0 Nm {10.5 kgf
cm}
(3) The wheel bearing starting torque should be within the
limit and the hub should be free of binding or rough motion
when turned.
2. WHEEL BEARING AXIAL PLAY CHECK
(1) Check the wheel bearing for axial play.
Limit: 0.05 mm
(2) If the specified torquing range (196 to 255 Nm {20.0
to 26.0 kgf
m}) does not bring the wheel bearing axial
play into the limit, replace the rear hub assembly.
Washer
MB990767196 – 255 Nm
{20.0 – 26.0 kfg
m}
MB990326 MB991000
(MB990998)
Wood block 196 – 255 Nm
{20.0 – 26.0 kfg
m} MB991017
Wood block
Wood block
MB991017