ESP MITSUBISHI LANCER EVOLUTION VI 1999 User Guide

REAR AXLE – Troubleshooting <AYC>27-6
4. INSPECTION PROCEDURES FOR DIAGNOSIS CODES
Code No. 12: Power supply voltage (valve power supply)
systemProbable cause
This code is output when the AYC-ECU power supply voltage drops below, goes
beyond, a specified level.
Defective harness or connector

Defective battery

Defective AYC-ECU
NOTE
Refer to the corresponding item if any other diagnosis code is being output.
Is the battery voltage correct?NG
Replace
OK
Measure at B-96 AYC-ECU connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON

Voltage across 31 and body ground
OK:System voltageNGCheck the following connectors:
B-96, B-94, B-49, B-75, B-76
OK
Check the trouble symptom.
NG
Check and repair harness between
ignition switch (IG
2) and AYC-ECU. OKReplace AYC-ECU.NG
Repair
Code Nos. 21, 22, 23, 24: Wheel speed sensor systemProbable cause
This code is output if any one of three wheel speed sensors fails to provide an input
even after the other wheel exceeded 8 km/h.
Defective harness or connector

Defective ABS-ECU

Defective AYC-ECU
<Vehicles with ABS>
NG
Replace AYC-ECU.
OK
Replace ABS-ECU.
NG
Check harness between AYC-ECU
and ABS-ECU.NG
Repair
OK
Check the trouble symptom.
Is an ABS diagnosis code No. 21, 22,
23, or 24 output?YESRefer to Group 35B – Troubleshooting
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)OKCheck the following connector:
B-95
OK
Check the trouble symptom.
NG
Check the following connectors:
B-24, B-95NG
RepairNG
Repair

REAR AXLE – Troubleshooting <AYC>27-8
Code No. 25: Wrong-diameter tireProbable cause
This code is output if the speed of any one of the four wheels exceeds a specified
level with respect to the average of the four wheel speed sensor outputs when the
steering wheel is in the straight-ahead position and the vehicle speed exceeds 20
km/h. At this time, the warning lamp does not light up.
Defective harness or connector

Defective AYC-ECU

Defective ABS-ECU
<Vehicles with ABS>
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)OKCheck the following connector:
B-95
YES
Is ABS diagnosis code No. 15 output?YESGroup 35* – Refer to Troubleshooting
Are correct tires mounted on all four
wheels?NO
Repair
NG
Repair
<Vehicles without ABS>
NO
Repair
NOCheck and repair the harness between
wheel 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 wheel speed sensor output volt-
age. (Refer to p. 27-37.)NGCheck wheel speed sensor and ABS
rotor. (Refer to Group 35B.)
YES
Check Wheel speed sensor for instal-
lation.NG
Repair
Are correct tires mounted on all four
wheels?
NG
Replace

REAR AXLE – Troubleshooting <AYC>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 <AYC>27-19
Code No. 83: Electric pump systemProbable cause
This code is output if the pressure switch is not set to low-pressure position despite
the AYC-ECU’s command to change the driving force.
Defective accumulator pressure switch

Defective harness or connector
OK
Replace AYC-ECU.
NG
Check the harness between AYC-ECU
and accumulator pressure switch.NG
Repair
OK
Check the trouble symptom.
NG
Check and repair the harness between
accumulator pressure switch and body
ground.
OK
Check the trouble symptom.
(2) NG
Check the following connectors:
F-31, F-30NG
Repair
NO
Measure at F-31 accumulator pressure
switch connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON
(1) Voltage across 2 and body ground
OK:System voltage
(2) Continuity across 1 and body
ground
OK:ConductingOKReplace the hydraulic unit for a defec-
tive accumulator pressure switch.
OK
Check and repair the harness between
AYC relay and AYC motor.
NO
Is diagnosis code no. 71, 72, or 73
output?YES
Check the proportioning valve
system (code no. 71).
(Refer to P.27-14.)

Check the directional control valve
(right) system (code no. 72).
(Refer to P.27-15.)

Check the directional control valve
(left) system (code no. 73).
(Refer to P.27-16.)
(1) NGCheck the following connectors:
B-95, B-94, D-06, F-30, F-31NG
Repair
Does the AYC motor continue turning
when the ignition switch is turned ON?YESCheck the AYC relay for continuity.
(Refer to P.27-42.)NG
Repair

REAR AXLE – Troubleshooting <AYC>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.

37A-1
STEERING
CONTENTS
GENERAL 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Outline of Change 2. . . . . . . . . . . . . . . . . . . . . . . . .
STEERING WHEEL AND SHAFT* 2. . . . . . . .
POWER STEERING GEAR BOX* 5. . . . . . . . .
WARNINGS REGARDING SERVICING OF SUPPLEMENTAL RESTRAINT SYSTEM (SRS) EQUIPPED VEHICLES
WARNING!
(1) Improper service or maintenance of any component of the SRS, or any SRS-related component, can lead to personal
injury or death to service personnel (from inadvertent firing of the air bag) or to the driver and passenger (from rendering
the SRS inoperative).
(2) Service or maintenance of any SRS component or SRS-related component must be performed only at an authorized
MITSUBISHI dealer.
(3) MITSUBISHI dealer personnel must thoroughly review this manual, and especially its GROUP 52B – Supplemental
Restraint System (SRS) before beginning any service or maintenance of any component of the SRS or any SRS-related
component.
NOTE
The SRS includes the following components: SRS-ECU, SRS warning lamp, air bag module, clock spring and interconnecting
wiring. Other SRS-related components (that may have to be removed/installed in connection with SRS service or maintenance) are
indicated in the table of contents by an asterisk (*).

SRS – SRS-ECU / Air Bag Modules and Clock Spring52B-25
INSTALLATION SERVICE POINTS
ASRS-ECU INSTALLATION
Caution
The SRS may not activate if SRS-ECU is not installed
properly, which could result in serious injury or death
to the vehicle’s driver or front passenger.
BPOST-INSTALLATION INSPECTION
1. Reconnect the negative battery terminal.
2. Turn the ignition key to the “ON” position.
3. Does the “SRS” warning lamp illuminate for about 7
seconds, and then remain extinguished for at least 5
seconds after turning OFF?
4. If yes, SRS system is functioning properly.
If no, consult page 52B-6.
INSPECTION

Check the SRS-ECU and brackets for dents, cracks or
deformation.

Check connector for damage, and terminals for
deformation.
Caution
If a dent, crack, deformation or rust is discovered,
replace the SRS-ECU with a new one.
NOTE
For checking of the SRS-ECU other than described above,
refer to the section concerning troubleshooting. (Refer
to P.52B-6.)
AIR BAG MODULES AND CLOCK SPRING
Caution
1. Disconnect the battery (–) terminal and wait
for 60 seconds or more before starting work.
Furthermore, the disconnected battery
terminal should be covered with tape to
insulate it. (Refer to P.52B-3.)
2. Never attempt to disassemble or repair the
air bag modules or clock spring.
If faulty, replace it.
3. Do not drop the air bag modules or clock
spring or allow contact with water, grease
or oil.
Replace it if a dent, crack, deformation or
rust is detected.
4. The air bag modules should be stored on
a flat surface and placed so that the pad
surface is facing upward.
Do not place anything on top of it.5. Do not expose the air bag modules to
temperatures over 93C.
6. Both driver’s side and front passenger’s
side air bag modules should be replaced
with new ones once the respective air bags
were deployed. The clock springs should
also be checked and replaced with new ones
if considered abnormal.
7. Wear gloves and safety glasses when
handling air bags that have already
deployed.
8. An undeployed air bag module should only
be disposed of in accordance with the
procedures (Refer to P.52B-32.)
SRS warning lamp

SRS – Air Bag Modules and Clock Spring52B-31
3. Check that there is continuity between terminal (3) of
the clock spring No.1 connector and the No. 2 connector.
4. Joint the No.3 connector and No.4 connector of the clock
spring to connector No.6 and connector No.4 respectively,
of the SRS check harness.
NOTE
When joining SRS check harness connector No.4 align
its white paint with the hollow portion of the No.4 connector
of the clock spring.
5. Check for continuity between terminal 22 and terminal
25, and terminal 23 and terminal 24, of SRS Check
Harness connector No. 5 using a digital multi-meter.
14
2 3
SRS check harness (MB991613)
Clock spring
connector 4
Clock spring
connector 3
View A
4
5
6A

54-1
CHASSIS
ELECTRICAL
CONTENTS
GENERAL 3. . . . . . . . . . . . . . . . . . . . . . . . . .
BATTERY 3. . . . . . . . . . . . . . . . . . . . . . . . . . .
SERVICE SPECIFICATION 3. . . . . . . . . . . . . . .
ON-VEHICLE SERVICE 3. . . . . . . . . . . . . . . . . .
IGNITION SWITCH <EXCEPT
EVOLUTION-VI WITH IMMOBILIZER
SYSTEM> 6. . . . . . . . . . . . . . . . . . . . . . . . . . .
SPECIAL TOOL 6. . . . . . . . . . . . . . . . . . . . . . . . .
TROUBLESHOOTING 6. . . . . . . . . . . . . . . . . . . .
IGNITION SWITCH 11. . . . . . . . . . . . . . . . . . . . . .
IGNITION SWITCH AND IMMOBILIZER
SYSTEM <EVOLUTION-VI WITH
IMMOBILIZER SYSTEM> 13. . . . . . . . . . .
SPECIAL TOOL 13. . . . . . . . . . . . . . . . . . . . . . .
TROUBLESHOOTING 13. . . . . . . . . . . . . . . . . .
IGNITION SWITCH AND IMMOBILIZER
SYSTEM 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
COMBINATION METERS 22. . . . . . . . . . . .
SERVICE SPECIFICATIONS 22. . . . . . . . . . . .
SEALANT 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SPECIAL TOOLS 23. . . . . . . . . . . . . . . . . . . . . .
TROUBLESHOOTING 24. . . . . . . . . . . . . . . . . .
CONTINUED ON NEXT PAGE
WARNINGS REGARDING SERVICING OF SUPPLEMENTAL RESTRAINT SYSTEM (SRS) EQUIPPED VEHICLES
WARNING!
(1) The service personnel must thoroughly review this manual, and especially its GROUP 52B – Supplemental Restraint
System (SRS) before beginning any service or maintenance of any component of the SRS or any SRS-related
component.
(2) When removing or installing the components indicated in the table of contents by an astarisk (*), use utmost care so
as not to apply any strong shock to SRS components.
NOTE
The SRS includes the following components: SRS-ECU, SRS warning lamp, air bag module, clock spring and interconnecting
wiring. Other SRS-related components (that may have to be removed/installed in connection with SRS service or maintenance) are
indicated in the table of contents by an asterisk (*).