1998 MITSUBISHI LANCER EVOLUTION IV Workshop Manual

ABS – Troubleshooting35B-10
Code No. 71: Acceleration sensor (lateral acceleration)
systemProbable cause
This code is output under either of the following conditions:

The output from the acceleration sensor (lateral acceleration) becomes 0.5 V or
less, or 4.5 V or more.

The acceleration sensor (lateral acceleration) harness is open- or short-circuited.
Defective acceleration sensor (lateral acceleration)

Defective harness or connector

Defective ABS-ECU
OK
Check the trouble symptom.NGReplace ABS-ECU.
OK
Check the trouble symptom.NGCheck and repair the harness between
acceleration sensor (lateral accelera-
tion) and ABS-ECU.
OK
Check the trouble symptom.NGCheck and repair the harness between
general-purpose fuse No. 6 and
acceleration sensor (lateral accelera-
tion).
OK
Replace ABS-ECU.
OK
Check the following connector:
B-24NG
Repair
OK
Measure at B-24 ABS-ECU connector.

Connect the connector.

Ignition switch: ON

Voltage across 17 and 18
OK:2.4 – 2.6 V
(horizontal position)NGCheck the following connectors:
B-24, D-32, B-52NG
Repair
NG
Check the harness between accelera-
tion sensor (lateral acceleration) and
ABS-ECU.NG
Repair
OK
Check the trouble symptom.
OK
Check the acceleration sensor (lateral
acceleration). (Refer to P.35B-17.)NG
Replace
(1) NGCheck the following connectors:
D-32, B-49, B-75NG
Repair
Check the following connector:
D-32, B-49, B-75NG
Repair
(2) NG
Measure at D-32 acceleration sensor
(lateral acceleration) connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON
(1) Voltage across 1 and body ground
OK:Battery voltage
(2) Continuity across 3 and body
ground
OK:Conducting

ABS – Troubleshooting35B-11
3. INSPECTION CHART FOR TROUBLE SYMPTOMS
Get an understanding of the trouble symptoms and check according to the inspection procedure chart.
Trouble symptomsInspection pro-
cedure No.Reference page
When the ignition key is turned to “ON” (engine stopped), the ABS warning lamp
does not illuminate.135B-12
Even after the engine is started, the ABS warning lamp remains illuminated.235B-13
After the ignition key is turned to “ON”, the ABS warning lamp blinks twice, and
when turned to “START”, it illuminates. When returned to “ON”, the lamp
flashes once, and then switches off.335B-13
When the ignition key is turned to “START”, the ABS warning lamp does not
illuminate.435B-14
Brake operation is abnormal535B-14
Caution
(1) If steering movements are made when driving at high speed, or when driving on road surfaces
with low frictional resistance, or when passing over bumps, the ABS may operate even though
sudden braking is not being applied. Because of this, when getting information from the customer,
check if the problem occurred while driving under such conditions as these.
(2) During ABS operation, the brake pedal may vibrate or may not be able to be depressed. Such
phenomena are due to intermittent changes in hydraulic pressure inside the brake line to prevent
the wheels from locking and is not an abnormality.

ABS – Troubleshooting35B-12
4. INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS
INSPECTION PROCEDURE 1
When the ignition key is turned to “ON” (engine stopped),
the ABS warning lamp does not illuminate.
Probable cause
The ABS-ECU turns the valve relay ON → OFF → ON for initial checking when
it is powered ON. Accordingly, the ABS warning lamp illuminates twice even if the
circuit between the ABS warning lamp and ABS-ECU is faulty.
The cause may be an open circuit in the lamp power supply circuit, a blown lamp,
an open circuit between the ABS warning lamp and ABS-ECU or between the ABS
warning lamp and the valve relay.
Blown fuse

Burn out ABS warning lamp bulb

Malfunction of wiring harness or connector
OK
Check the trouble symptom.NGReplace the combination meter.
OK
Check the following connectors:
B-08, B-09NG
Repair
OK
Check the trouble symptom.NGCheck the harness wire, and repair
if necessary.

Between ignition switch and ABS
warning lamp
OK
Check the motor for operation.NGCheck the harness wire, and repair
if necessary.

Between ABS warning lamp and
ABS-ECU

Between ABS warning lamp and
valve relay
OK
Check the following connectors:
A-76, B-09, B-52NG
Repair
OK
Measure at the combination meter con-
nector B-09.

Disconnect the connector, and
measure at the combination meter
side connector.

Ignition switch: ON

ABS warning lamp condition when
terminal 12 is grounded.
OK:IlluminatesNGCheck whether the ABS warning lamp
bulb is burnt out.NG
OK
Measure at the combination meter con-
nector B-08.

Disconnect the connector and
measure at the harness side
connector.

Ignition switch: ON

Voltage between 42 and body
ground
OK:Battery voltageNGCheck the following connectors:
B-08, B-75, B-76NG
Repair
Fuse check
General-purpose fuse No.4NGReplace fuse after eliminating the
cause.
Replace the ABS warning lamp bulb.

ABS – Troubleshooting35B-13
INSPECTION PROCEDURE 2
Even after the engine is started, the ABS warning lamp
remains illuminated.
Probable cause
The cause is probably a short-circuit in the ABS warning lamp illumination circuit.
Malfunction of combination meter

Malfunction of ABS-ECU

Malfunction of wiring harness (short circuit)
NOTE
This trouble symptom is limited to cases where ABS-ECU power supply is normal and the diagnosis
code is a normal diagnosis code.
NO
Check the harness wire, and repair if necessary.

Between ABS warning lamp and ABS-ECU

Between ABS warning lamp relay and valve relay
NO

Disconnect the ABS-ECU connector B-25.

Disconnect the valve relay connector A-76.

Ignition switch: ON

Does the ABS warning lamp go off?YESReplace the ABS-ECU.
Does the ABS warning lamp stay illuminated when the connector
B-52 is disconnected and the ignition switch is turned to ON?YESReplace the combination meter.
INSPECTION PROCEDURE 3
After the ignition key is turned to “ON”, the ABS warning
lamp blinks once, and when turned to “START”, it
illuminates. When returned to “ON”, the lamp flashes
once, and then switches off.
Probable cause
The ABS-ECU causes the ABS warning lamp to illuminate during the initial check.
During the initial check, the valve relay turns from off to on, off and back to on again.
If there is an open circuit in the harness between the ABS-ECU and the ABS warning
lamp, the lamp will illuminate only when the valve relay is OFF during valve relay
test, etc.
Malfunction of wiring harness or connector

Malfunction of ABS-ECU
OK
Check the trouble symptom.NGCheck the harness between the com-
bination meter and the ABS-ECU, and
repair if necessary.
OK
Check the trouble symptom.NGReplace the ABS-ECU.
OK
Check the following connector:
B-25NG
Repair
Measure at ABS-ECU connector B-25.

Disconnect the connector and
meeasure at the harness side.

Disconnect valve relay connector
A-76.

Ignition switch: ON

Voltage between 50 and body
ground
OK:Battery voltageNGCheck the following connector:
B-25NG
Repair

ABS – Troubleshooting35B-14
INSPECTION PROCEDURE 4
When the ignition key is turned to “START”, the ABS
warning lamp does not illuminate.
Probable cause
The ABS-ECU is powered through IG2 which is turned off when the ignition key
is in START position. The ABS warning lamp is powered through IG1 which is not
turned off even when the ignition key is in START position. So the cause must be
a defective circuit on valve relay side.
Malfunction of wiring harness or connector

Malfunction of valve relay
OK
Check the trouble symptom.NGCheck the harness between the com-
bination meter and valve relay, and
repair if necessary.
OK
Check the motor for operation.NGCheck the harness between the valve
relay and ground, and repair if neces-
sary.
OK
Check the following connector:
A-76NG
Repair
OK
Measure at valve relay connector A-76.

Disconnect the connector and
measure at the harness side.

Disconnect ABS-ECU connector
B-25.

Ignition switch: ON

Voltage between 3 and body
ground
OK:Battery voltageNGCheck the following connectors
and diode:
A-76, B-26NG
Repair
ABS valve relay check.NGReplace the valve relay.
INSPECTION PROCEDURE 5
Brake operation is abnormal
Probable cause
The varies depending on the driving conditions and the road surface conditions, so
problem diagnosis is difficult. However, if a normal diagnosis code is displayed, carry
out the following inspection.
Improper installation of wheel speed sensor

Incorrect sensor harness contact

Foreign material adhering to wheel speed sensor

Malfunction of wheel speed sensor

Malfunction of wheel bearing

Malfunction of hydraulic unit

Malfunction of ABS-ECU
NG
Repair
Hydraulic unit checkOKWheel speed sensor inspection. [Refer to Inspection Procedure
for “when either of diagnosis codes No. 11 to 14 is output” (P.35B-3).]

ABS – Troubleshooting35B-15
5. CHECK AT ABS-ECU TERMINALS
5-1 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
1Solenoid valve OUT (FL) outputIgnition switch: ON (after initial check)Battery voltage
2Solenoid valve OUT (RR) outputIgnition switch: ON (after initial check)Battery voltage
3Solenoid valve IN (RR) outputIgnition switch: ON (after initial check)Battery voltage
4Acceleration sensor (longitudinal
acceleration) inputIgnition switch: ON2.4 – 2.6 V
(horizontal position)
11Wheel speed (FL) outputVehicle stationary1 V or less
Moving forward slowly0 – 5 V
13ABS-ECU power supplyIgnition switch: ONBattery voltage
14Solenoid valve IN (FL) outputIgnition switch: ON (after initial check)Battery voltage
15GroundAt all times0 V
17Acceleration sensor groundAt all times0 V
18Acceleration sensor (lateral
acceleration) inputIgnition switch: ON2.4 – 2.6 V
(horizontal position)
24Wheel speed (RL) outputVehicle stationary1 V or less
Moving forward slowly0 – 5 V
25GroundAt all times0 V
32ABS-ECU backup power supplyAt all timesBattery voltage
33Wheel speed (FR) outputVehicle stationary1 V or less
Moving forward slowly0 – 5 V
34Stop lamp switch inputStop lamp switch: ONBattery voltage
Stop lamp switch: OFF0 V
37Valve relay outputIgnition switch:
ON
When relay is ON0 V
ONWhen relay is OFFBattery voltage
38Motor relay outputIgnition switch:
ON
When motor is energized0 V
ONWhen motor is deenergizedBattery voltage
40Solenoid valve OUT (RL) outputIgnition switch: ON (after initial check)Battery voltage
41Solenoid valve OUT (FR) outputIgnition switch: ON (after initial check)Battery voltage
42GroundAt all times0 V

ABS – Troubleshooting35B-16
Terminal
No.Normally Check requirement Check item
44Wheel speed (RR) outputVehicle stationary1 V or less
Moving forward slowly0 – 5 V
48Valve relay monitor inputIgnition switch: ON (after initial check)Battery voltage
49Motor relay monitor outputIgnition switch:
ON
When motor is energized0 V
ONWhen motor is deenergizedBattery voltage
50ABS warning lamp outputIgnition switch:
ON
When lamp is offBattery voltage
ONWhen lamp is on0 V
51Solenoid valve IN (RL) outputIgnition switch: ON (after initial check)Battery voltage
52Solenoid valve IN (FR) outputIgnition switch: ON (after initial check)Battery voltage
5-2 LISTING OF RESISTANCE AND CONTINUITY ACROSS CONNECTOR TERMINALS ON
HARNESS SIDE
(1) Measure the resistance and check for continuity with the ignition switch in the ”OFF” position and
ABS-ECU connector disconnected.
(2) Measure the resistance and check for continuity across terminals listed below.
(3) Fig. below shows the arrangement of terminals.
Terminal No.Signal nameNormally
1 – body groundSolenoid valve OUT (FL) output4.04 – 4.54 Ω
2 – body groundSolenoid valve OUT (RR) output4.04 – 4.54 Ω
3 – body groundSolenoid valve IN (RR) output8.04 – 9.04 Ω
7 – 20Wheel speed sensor (FL) input1.4 – 1.8 kΩ
8 – 21Wheel speed sensor (RR) input1.4 – 1.8 kΩ
9 – 22Wheel speed sensor (RL) input1.4 – 1.8 kΩ
10 – 23Wheel speed sensor (FR) input1.4 – 1.8 kΩ
14 – body groundSolenoid valve IN (FL) output8.04 – 9.04 Ω
15 – body groundGroundConducting
25 – body groundGroundConducting
40 – body groundSolenoid valve OUT (RL) output4.04 – 4.54 Ω
41 – body groundSolenoid valve OUT (FR) output4.04 – 4.54 Ω
42 – body groundGroundConducting
48 – body groundValve relay monitor inputConducting
49 – body groundMotor relay monitor inputConducting
51 – body groundSolenoid valve IN (RL) output8.04 – 9.04 Ω
52 – body groundSolenoid valve IN (FR) output8.04 – 9.04 Ω

ABS – On-vehicle Service / Lateral Acceleration Sensor35B-17
ON-VEHICLE SERVICE
WHEEL SPEED SENSOR OUTPUT VOLTAGE
MEASUREMENT
The EVOLUTION-V has the ABS-ECU connector terminal
arranged as shown at left. Accordingly, the terminals to
measure the output voltage of the wheel speed sensors are
different from EVOLUTION-V.
Follow the conventional procedures except these pick-out
terminals.
Measurement terminals:
Front LHFront RHRear LHRear RH
71098
20232221
LATERAL ACCELERATION SENSOR
INSPECTION
Use the same procedures as those for the conventional
longitudinal acceleration sensor.
ABS-ECU connector harness side
Longitudinal
acceleration
sensor
Lateral acceleration sensor