light MITSUBISHI LANCER EVOLUTION IV 1998 User Guide

REAR AXLE – Troubleshooting <AYC>27-9
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: OK

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?YESTroubleshooting
Are correct tires mounted on all four
wheels?NO
Repair
NG
Repair
<Vehicles without ABS>
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.
YES
Check speed sensor for installation.NG
Repair
Are correct tires mounted on all four
wheels?NO
Repair
NG
Replace

REAR AXLE – Troubleshooting <AYC>27-21
5. INSPECTION CHART FOR TROUBLE SYMPTOMS
Trouble symptomInspection
procedure No.Ref. page
AYC warning lamp does not light up when the ignition key is turned to “ON” (engine
stationary).127-21
AYC warning lamp remains lit up after the engine has started.227-22
AYC is inoperative.
Unable to start or accelerate on slippery road surfaces.327-22
Rear tires are noisy during low-speed cornering.
Vehicle skews.427-23
6. INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS
INSPECTION PROCEDURE 1
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:Battery voltageNGCheck the following connectors:
B-08, B-74, B-76NG
Repair

REAR AXLE – On-vehicle Service <Vehicles with AYC>27-32
Waveform Observation Points
SymptomProbable causeAction
Waveform amplitude is too small, or no
waveform.Defective 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 speed sensorCorrect sensor installation.
Missing or collapsed rotor toothReplace rotor.
Caution
Since the 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 speed
sensor output voltage waveform should therefore be checked also by rocking the sensor harness
so that driving on rough roads may be simulated.
8. 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

CHASSIS ELECTRICAL – Headlamp54-32
HEADLAMP
SERVICE SPECIFICATIONS
ItemsStandard valueLimit
Headlamp
aiming
High
beam
Vertical direction25’ (22 mm) below horizontal line–
aiming
[Parenthe-
sized are
allowable
beam
Horizontal
directionLeft head-
lampParallel to direction of vehicle travel–
allowable
beam axis
deviations 3
m ahead of
Right head-
lamp15’ (13 mm) leftward from vertical line (V)–
m ahead of
headlamp.]Low
beam
Vertical direction25’ (22 mm) below horizontal line–p]beam
Horizontal directionPosition where 15* rising section intersects
vertical line (V)–
Headlamp intensity cd (Center of high-beam high intensity
zone)–15,000 or
more per
light
Cautions in Handling Headlamp Assembly
Each headlamp assembly has a plastic outer lens on. Observe the do’s and don’ts below when
handling the headlamps.

Do not leave the headlamps lit for longer than 3 minutes with a protective cover on.

Do not mask the outer lens surface by taping or in any other way.

Do not scrub the outer lens surface with a pointed tool.

Use the designated wax remover for cleaning the outer lens surface. Rinse it thoroughly.

Use the designated genuine bulbs.
SPECIAL TOOLS
ToolNumberNameUse
MB991502MUT-II sub as-
semblyETACS-ECU input signal checking

CHASSIS ELECTRICAL – Headlamp54-33
TROUBLESHOOTING
DIAGNOSIS FUNCTION
INPUT SIGNAL INSPECTION POINTS <VEHICLES WITH ETACS-ECU>
Refer to Group 00 – How to Use Troubleshooting / Inspection Service Points.
The lighting monitor buzzer does not sound even when
the ignition key is removed with the tail lamps or
headlamps ON and the driver’s side door open. [However,
the key reminder warning buzzer sounds when inserting
the key into the ignition key cylinder.
Probable cause
The cause is probably a malfunction of the lighting switch input circuit system or
a malfunction of ETACS-ECU or buzzer ECU. When the key reminder warning buzzer
is sounding, the lighting monitor warning buzzer does not sound even if the tail lamps
or headlamps are lit.
Malfunction of harness or connector

Malfunction of ETACS-ECU

Malfunction of buzzer ECU
<Vehicles with ETACS-ECU>
MUT-II Pulse check
OK:MUT-II buzzer sounds once
when the lighting switch is
turned from OFF to TAIL or
HEAD.NG
Check the following connectors.
B-79Repair
OK
Check trouble symptom.NGOK
Replace the ETACS-ECU.
<Vehicles with buzzer ECU>
NG
Check the harness in the junction block.NG
Replace the ETACS-ECU or the buzzer
ECU.OKRepair NG

CHASSIS ELECTRICAL – Headlamp54-35
Standard values:
Vertical direction25’ (22 mm) below hori-
zontal line (H)
Horizontal
directionLeft headlampParallel to direction of
vehicle travel
Right head-
lamp15’ (13 mm) leftward
from vertical line (V)
Caution:
(1) Perform aiming adjustments, one light at a time,
with the other headlamp disconnected so as not
to be lit unless circumstances compel otherwise.
When reconnecting the headlamps, be careful not
to upset their aim. Do not leave the headlamps
on for any longer than 3 minutes if their outer
lenses are covered with a surface covering
impervious to light.
(2) Do not mask the outer lenses by taping or in any
other way.
(3) Aiming adjustment must be completed with the
aiming adjustment screws turned in the tightening
direction.
INTENSITY MEASUREMENT
1. Position the tester so that its light sensor faces each
headlamp center to center at the appropriate distance
shown.
2. Maintain an engine speed of 2,000 r/minto keep the battery
in the charged condition.
3. Check that the high-beam headlamp intensity at the center
of the high intensity zone satisfies the limit value.
Limit: 15,000 cd or more per headlamp
Caution
(1) Perform intensity measurement, one headlamp at
a time, with the low-beam lamp and the other
headlamp disconnected from the battery unless
circumstances compel otherwise. Do not leave
the headlamps on for any longer than 3 minutes
if their outer lenses are covered with a surface
covering impervious to light.
(2) Do not mask the outer lens surfaces by taping
or in any other way.
HEADLAMP BULB REPLACEMENT
1. Disconnect the connector.
2. Remove the socket cover.
3. Unhook the spring which secures the bulb, and then
remove the bulb.
Caution
Do not touch the surface of the bulb with hands or
dirty gloves. If the surface does become dirty, clean
it with alcohol or thinner, and let it dry thoroughly
before installing.
<Left headlamp>
Lamp center
Vertical direction
Vertical direction High
intensity
zone
center
(optical
axis)
High
intensity
zone
center
(optical
axis)High intensity zone
High intensity zoneLamp center <Right headlamp>V
H
V
H
Screen type tester: 3 m Converging
lens type tester: 1 m
Spring

CHASSIS ELECTRICAL – Headlamp54-37
REMOVAL SERVICE POINT
AFRONT TURN-SIGNAL LAMP REMOVAL
1. Loosen the tapping screw connecting the headlamp to
the front turn-signal lamp. Put a screwdriver in the space
produced between the headlmap and the front turn-signal
lamp.
2. Prying the screwdriver in the direction shown, thrust the
front turn-signal lamp in the direction of the vehicle.
3. Unplug the connector and remove the front turn-signal
lamp.
INSTALLATION SERVICE POINT
AHEADLAMP INSTALLATION
Tighten attaching bolts and nuts in the order of A, B, C and
D.
INSPECTION
LIGHTING SWITCH, DIMMER/PASSING SWITCH
CONTINUITY CHECK
Switch positionTerminal No.
Connector AConnector B
56712346
LIGHTING
SWITCH
OFF
SWITCHTAIL
HEAD
DIMMER/
PASSING
LOWER
PASSING
SWITCHUPPERSWITCH
PASSING
Tapping screw
A
D B C
Connector A Connector B

CHASSIS ELECTRICAL – Front Fog Lamp54-40
Standard values:
Vertical direction2° (349 mm) below horizontal line
(H)
Horizontal direction3° (524 mm) leftward from
vertical line (V)
Caution:
(1) Perform aiming adjustments, one light at a time,
with the other headlamp disconnected so as not
to be lit unless circumstances compel otherwise.
When reconnecting the headlamps, be careful not
to upset their aim. Do not leave the headlamps
on for any longer than 3 minutes if their outer
lenses are covered with a surface covering
impervious to light.
(2) Do not mask the outer lenses by taping or in any
other way.
(3) Aiming adjustment must be completed with the
aiming adjustment screws turned in the tightening
direction.
FOG LAMP BULB REPLACEMENT
1. Remove the fog lamp.
2. Remove the cover.
3. Unhook the spring which secures the bulb and then
replace the bulb.
Caution
(1) Do not touch the surface of the bulb with hands
or dirty gloves. If the surface does become dirty,
clean it with alcohol or thinner, and let it dry
thoroughly before installing.
(2) To prevent the clouding of lens and ingress of
water into the lamp unit, install the socket cover
correctly.
Lamp center
Vertical
direction
High
intensity
zone
center
(optical
axis)High intensity zone
Horizontal directionV
H
Cover

CHASSIS ELECTRICAL – Rear Combination Lamp54-42
REAR COMBINATION LAMP
TROUBLESHOOTING
For the troubleshooting of the lighting monitor warning buzzer, refer to P.54-33.
REAR COMBINATION LAMP
REMOVAL AND INSTALLATION
Caution: SRS
Before removal of air bag module and clock spring, refer to GROUP 52B – SRS Service Precautions and Air Bag
Module and Clock Spring.
2
1
3
1. Column switchRear combination lamp removal
steps
2. Rear end trim
3. Rear combination lamp
INSPECTION
LIGHTING SWITCH CONTINUITY CHECK
Switch positionTerminal No.
Connector BConnector A
5671
LIGHTING
SWITCH
OFF
SWITCHTAIL
HEAD
Connector A Connector B