engine MITSUBISHI LANCER EVOLUTION VI 1999 Workshop Manual

REAR AXLE – Troubleshooting 27-22
INSPECTION PROCEDURE 3
AYC warning lamp does not light up when the ignition key
is turned to “ON” (engine stationary).
Probable cause
The lamp power supply circuit is probably open-circuited, lamp bulb is out, or the
circuit between AYC warning lamp and AYC-ECU or AYC-ECU itself is defective.
Blown fuse

AYC warning lamp out

Defective harness or connector

Defective AYC-ECU
NG
Check and repair the harness between
ignition switch (IG
2) and AYC warning
lamp.
OK
Check the trouble symptom.
OK
Replace combination meter.
NG
Check the harness between AYC
warning lamp and AYC-ECU.NG
Repair
OK
Check the trouble symptom.OK
Replace AYC-ECU.
OK
Check the following connectors:
B-96, B-94, B-08NG
Repair
OK
Measure at B-96 AYC-ECU connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON

Warning lamp when 36 is grounded
to body
OK:Lit upNGCheck the lamp bulb.NG
Replace
Measure at B-08 combination meter
connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON

Voltage across 48 and body ground
OK:Symptom voltageNGCheck the following connectors:
B-08, B-74, B-76NG
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 27-28
CHECK AT AYC-ECU TERMINALS
TERMINAL VOLTAGE LISTING

The voltage is to be measured across each terminal and ground terminal.

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 inputWhen MUT-II is connected1 V or less
When MUT-II is disconnectedSystem voltage
11Stop lamp switchIgnition switch:
ON
Stop lamp switch: ONSystem voltage
ON
Stop lamp switch: OFF1 V or less
12*1ABS monitorWhen ABS monitor is activatedSystem voltage
When ABS monitor is deactivated1 V or less

REAR AXLE – Troubleshooting 27-29
Terminal
No.Normally Check requirement Check item
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
18TPSIgnition switch:
ON
Accelerator pedal: Fully closed0.3 – 1.0 V
ON
Accelerator pedal: Fully open4.5 – 5.0 V
23Diagnosis data input/outputWhen MUT-II is connectedSerial communica-
tion with MUT-II
When MUT-II is disconnected1 V or less
24Idle position switchIgnition switch:
ON
Accelerator pedal: Fully closed2 V or less
ON
Accelerator pedal: Fully open4.5 – 5.0 V
25Accumulator pressure
switchIgnition switch:
ONAccumulator internal pressure:
Low2 V or less
Accumulator internal pressure:
HighSystem voltage
26ECU groundAt all times0 V
31AYC-ECU power supplyIgnition switch: ONSystem voltage
Ignition switch: OFF0 V
35AYC motor relayIgnition switch:
ON
When motor is energizedSystem voltage
ON
When motor is deenergized2 V or less
36AYC warning lampIgnition switch:
ON
When lamp is OFFSystem voltage
ON
When lamp is ON2 V or less
37Directional control valve
(right)
Ignition switch:
ON
Right clutch: ONSystem voltage
(right)ON
Right clutch: OFF0 V
38Proportioning valveIgnition switch:
ONAYC-ON0 V to system volt-
age
AYC-OFF0 V
39ECU backup power supplyAt all timesSystem voltage
45Directional control valve
(left)
Ignition switch:
ON
Left clutch: ONSystem voltage
(left)ON
Left clutch: OFF0 V
46ECU groundAt all times0 V
NOTE
*1: Indicates the vehicles with ABS.

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 27-35
NOTE
(1) Hold the steering wheel in the neutral position.
(2) If the steering wheel is turned, it may happen that
the AYC system continues to operate (operation
sounds are heard from the torque transfer differential).
However, it does not mean a system failure. If such
a case is encountered, perform the following
operations with the steering wheel in the neutral
position to cancel the AYC function.

Disengage the clutch.

Set the transmission to neutral.

Stop the engine.
5. Operate the MUT-II (Item Nos.13 and 14) to activate
the torque transfer differential.
NOTE
(1) The forced activation (clutch operation mode) will be
automatically canceled after 1 minute 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 torque transfer
differential can not be executed.
6. Operate the MUT-II to confirm that the several speeds
of the wheels are as shown below, using the Data List
(Item Nos.07 and 08).

The speed of left rear wheel is more than 2 km/h
higher than that of right rear wheel.

The speed of right rear wheel is more than 2 km/h
higher than that of left rear wheel.
NOTE
If the above requirements are not satisfied, the system
is probably failed. Check the hydraulic pressure.
HYDRAULIC PRESSURE 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. Turn on the ignition switch.
4. Disconnect the joint between the hydraulic unit and the
hydraulic unit hose assembly. Connect the special tool
to the L port. To the R port, attach a blind plug or connect
the L port of the removed hydraulic unit hose assembly.
5. Operate the MUT-II (Item No.13) to activate the hydraulic
unit.
NOTE
(1) The forced activation (clutch left side operation check
mode) will be automatically canceled after 1 minute
operation.
It can also be canceled forcibly by operating the clear
key on the MUT-II.
MB991705
MD998330

REAR AXLE – On-vehicle Service 27-37
WHEEL SPEED SENSOR OUTPUT VOLTAGE
MEASUREMENT
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 wheel speed sensor as necessary.

Excessive clearance between the pole piece and rotor
of the wheel speed sensor

Defective wheel speed sensor
Waveform Check Using Oscilloscope
Check the harness and connector of the wheel speed sensor
for connection. Then, use an oscilloscope to check for output
voltage waveform of each 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 – On-vehicle Service 27-38
Waveform Observation Points
SymptomProbable causeAction
Waveform amplitude is too small, or no
waveform.Defective wheel speed sensorReplace sensor.
Waveform amplitude varies greatly. (No
problem ifthe smallest amplitude is 100
Excessive axle hub lateral and radial runoutReplace hub.
problem if the smallest amplitude is 100
mV or more)Poor AYC-ECU groundingRepair.
Noise on waveform or disturbed
waveform
Open-circuited sensorReplace sensor.
waveform
Open-circuited harnessRepair harness.
Improperly mounted wheel speed sensorCorrect sensor installation.
Missing or collapsed ABS rotor toothReplace ABS rotor.
Caution
Since the wheel speed sensor cable follows the movement of the front or rear suspension, it
may be open-circuited only when the vehicle is run on rough roads and not on ordinary road.
The wheel speed sensor output voltage waveform should therefore be checked also by rocking
the sensor harness so that driving on rough roads may be simulated.
ACTION WHEN BATTERY RUNS OUT
When the engine is started using a booster cable where the
battery has completely run down and you attempt to start
the vehicle without waiting for the battery to recover a certain
charge, the engine can misfire and you just cannot start to
move it. In such cases, charge the battery sufficiently; or,
remove the AYC fusible link from the engine compartment
relay box to make AYC inactive before attempting to start
the vehicle. When the fusible link is removed, the AYC warning
lamp lights up. After the battery has been recharged, fit the
fusible link back again and start the engine to ensure that
the AYC warning lamp is off.AYC fusible link

BASIC BRAKE SYSTEM – General / On-vehicle Service35A-2
GENERAL
OUTLINE OF CHANGE

The service procedures for left-hand drive vehicles have been established as described below.

The service procedures for the front and rear disc brakes have been changed since they had been
replaced by a different type.
ON-VEHICLE SERVICE
BRAKE PEDAL CHECK AND ADJUSTMENT

1. Turn up the carpet, etc under the brake pedal.
2. Measure the brake pedal height as illustrated. If the brake
pedal height is not within the standard value, follow the
procedure below.
Standard value: 163.5 –166.5 mm
(1) Disconnect the stop lamp switch connector.
(2) Adjust the brake pedal height by turning the operating
rod with pliers (with the operating rod lock nut
loosened), until the correct brake pedal height is
obtained.
(3) Secure by tightening the lock nut of the operating
rod.
(4) Push the stop lamp switch in the direction of the
pedal stroke until it stops. (The switch will slide if
it is pushed firmly.)
(5) Lift up the pedal until the operating rod is fully
extended, and then slide the stop lamp switch back
to the required position. Adjust the position of the
switch by turning it until the distance shown in the
illustration is correct.
(6) Connect the connector of the stop lamp switch.
(7) Check that the stop lamp is not illuminated with the
brake pedal unpressed.
3. With the engine stopped, depress the brake pedal two
or three times. After eliminating the vacuum in the power
brake booster, press the pedal down by hand, and confirm
that the amount of movement before resistance is met
(the free play) is within the standard value range.
Standard value: 3 – 8 mmOperating
rod
Operating
rod lock nutStop lamp
switch
Pedal down
Pedal up
Lock nut
Lock nut
Outer case
0.5 – 1.0 mm

BASIC BRAKE SYSTEM – On-vehicle Service35A-3
If the free play exceeds the standard value, it is probably
due to excessive play between the retaining ring bolt
and brake pedal arm.
Check for excessive clearance and replace faulty parts
as required.
4. Start the engine, depress the brake pedal with
approximately 490 N of force, and measure the clearance
between the brake pedal and the floorboard.
Standard value: 80 mm or more
If the clearance is outside the standard value, check for
air trapped in the brake line, clearance between the lining
and the drum and dragging in the parking brake.
Adjust and replace defective parts as required.
5. Turn back the carpet, etc.