1998 MITSUBISHI LANCER EVOLUTION IV ECU

35B-1
ANTI-LOCK
BRAKING
SYSTEM (ABS)
CONTENTS
TROUBLESHOOTING 2. . . . . . . . . . . . . . . . . . . .
1. Inspection Chart for Diagnosis Codes 2. . .
2. Inspection Procedure for Diagnostic
Trouble Codes 3. . . . . . . . . . . . . . . . . . . . . . . .
3. Inspection Chart for Trouble Symptoms 11
4. Inspection Procedure for Trouble
Symptoms 12. . . . . . . . . . . . . . . . . . . . . . . . . . .
5. Check at ABS-ECU Terminals 15. . . . . . . . .
ON-VEHICLE SERVICE 17. . . . . . . . . . . . . . . .
Wheel Speed Sensor Output Voltage
Measurement 17. . . . . . . . . . .
LATERAL ACCELERATION SENSOR 17. . .
WHEEL SPEED SENSOR 18. . . . . . . . . . . . . .

ABS – Troubleshooting35B-2
The EVOLUTION-V is provided with a lateral acceleration sensor in addition to the longitudinal acceleration
sensor, and the ABS-ECU connector is changed in terminal arrangement. When servicing EVOLUTION-V,
therefore, use the following service procedures.
TROUBLESHOOTING
1. INSPECTION CHART FOR DIAGNOSIS CODES
Diagnosis
code No.Diagnosis itemsReference Page
11Wheel speed sensor (FR) system (open- or short-circuit)35B-3
12Wheel speed sensor (FL) system (open- or short-circuit)35B-3
13Wheel speed sensor (RR) system (open- or short-circuit)35B-3
14Wheel speed sensor (RL) system (open- or short-circuit)35B-3
15Wheel speed sensor system (abnormal output signal)35B-4
16ABS-ECU power supply voltage system (abnormal voltage drop or rise)35B-5
21Wheel speed sensor (FR) system35B-2
22Wheel speed sensor (FL) system35B-2
23Wheel speed sensor (RR) system35B-2
24Wheel speed sensor (RL) system35B-2
27AYC monitor system (detective AYC)35B-6
32Longitudinal acceleration sensor circuit system35B-6
33Stop lamp switch system35B-7
41Solenoid valve (FR) system35B-7
42Solenoid valve (FL) system35B-7
43Solenoid valve (RR) system35B-7
44Solenoid valve (RL) system35B-7
51Valve relay system35B-8
53Motor relay system35B-9
63ABS-ECU failureReplace ABS-ECU.
71Lateral acceleration sensor system35B-10

ABS – Troubleshooting35B-3
2. INSPECTION PROCEDURE FOR DIAGNOSTIC TROUBLE CODES
Code Nos.11, 12, 13 and 14: Wheel speed sensor
(open circuit or short circuit)Probable cause
Code Nos.21, 22, 23 and 24: Wheel speed sensor
Code Nos 11, 12, 13 and 14 are output if the ABS-ECU detects an open circuit or
short-circuit in the (+) wire or (–) wire in any one of the four wheel speed sensors.
Malfunction of wheel speed sensor

Malfunction of wiring harness or connector

Malfunction of ABS-ECU
Code Nos.21, 22, 23 and 24 are output in the following cases.

When there is no input from any one of the four wheel speed sensors when travelling
at 8 km/h or more, even though open circuit can not be verified.

When a chipped or blocked-up ABS rotor is detected and if the anti-lock system
operates continuously because a malfunctioning sensor or a warped ABS rotor
is causing sensor output to drop.
Malfunction of wheel speed sensor

Malfunction of wiring harness or connector

Too much gap between the sensor and the rotor

Malfunction of ABS-ECU

Malfunction of wheel bearing
NG
Check the harness wire, and repair
if necessary.

Between each wheel speed sensor
and ABS-ECU
NG
Replace the ABS-ECU.
OK
Check the trouble symptom.
OK
Check the following connector:
B-24NG
Repair
NG
Repair
OK
Wheel bearing check
OK
ABS rotor check
OK
Wheel speed sensor output voltage
check (Refer to P.35B-17.)NGWheel speed sensor checkNG
Replace
OK
Check the following connectors:
B-24, B-52, B-17, A-26, A-50, D-04,
D-14, D-19OKCheck the trouble symptom.
OK
Measure at the ABS-ECU connector
B-24.

Disconnect the connector, and
measure at the harness side
connector.

Resistances between 8 and 21,
10 and 19, 7 and 20, 9 and 22
OK:1.4 – 1.8 kΩNGWheel speed sensor check
(Refer to P.35B-29.)NG
Replace
Wheel speed sensor installation checkNG
Replace
NG
Replace

ABS – Troubleshooting35B-4
Code No.15: Wheel speed sensor (abnormal output
signal)Probable cause
This code is output when there is an abnormality in the output signal from any one
of the four wheel speed sensors while driving (except for an open circuit or short
circuit).
The four vehicle tires are of different sizes

Malfunction of wheel speed sensor

Malfunction of wiring harness or connector

Malfunction of ABS-ECU

Malfunction of wheel bearing
OK
Check the harness wire, and repair
if necessary.

Between each wheel speed sensor
and ABS-ECU
OK
Wheel bearing checkNG
Replace the ABS-ECU.
OK
ABS rotor checkNG
RepairOK
Check the trouble symptom.
OK
Check the following connector:
B-24NG
Repair
OK
Check the trouble symptom.
OK
Wheel speed sensor output voltage
check (Refer to P.35B-17.)NGWheel speed sensor checkNG
Replace
YES
Wheel speed sensor installation checkNG
Repair
Are the sizes of all four tires identical?NOEquip the vehicle with tires of identical
sizes.
NG

ABS – Troubleshooting35B-5
Code No.16: ABS-ECU power supply system (abnormal
voltage drop or rise)Probable cause
This code is output if the ABS-ECU or valve relay power supply voltage drops below
or rises above the rated values.
The valve relay power supply voltage is detected based on the voltage in the valve
relay monitor line.
Malfunction of battery

Malfunction of wiring harness or connector

Malfunction of valve relay

Malfunction of ABS-ECU
Caution
If battery voltage drops or rises during inspection, this code will be output as well, making it
impossible to obtain correct diagnostic results.
Before carrying out the following inspection, check the battery level, and refill it if necessary.
OK
Replace ABS-ECU.
OK
Replace the ABS-ECU.
OK
Check the trouble symptom.NGCheck the harness wire, and repair
if necessary.

Between ignition switch and
ABS-ECU
OK
Check the trouble symptom.NGCheck the harness wire, and repair
if necessary.

Between general-purpose fuse
No. 6 and valve relay
NG
Repair
OK
Check the harness wire for short
circuit, and repair if necessary.

Between valve relay and hydraulic
unit

Between valve relay and motor
relayNG
Repair OK
NG
Check the harness wire, and repair
if necessary.

Between valve relay and ABS-ECUNG
Repair
OK
Check the trouble symptom.
OK
Check the trouble symptom.NGCheck the harness wire, and repair
if necessary.

Between general-purpose fuse
No. 6 and valve relay
OK
Measure at the ABS-ECU connector
B-25.

Connector connected

Ignition switch: ON
(1) Voltage between 37 and body
ground
OK:Battery voltage
(2) Voltage between 48 and body
ground
OK:Battery voltage(1) NGCheck the following connectors:
A-76, B-25NG
Repair
(2) NG
Check the following connectors:
A-76, B-25NG
Repair
OK
Check the valve relay.NG
Replace
OK
Check the trouble symptom.NGCheck the harness wire, and repair
if necessary.

Between fusible link No. 8 and
valve relay
OK
Measure at the valve relay connector
A-76.

Disconnect the connector, and
measure at the harness side
connector.

Ignition switch: ON
(1) Voltage between 6 and body
ground
OK:Battery voltage
(2) Voltage between 2 and body
ground
OK:Battery voltage(1) NGCheck the following connector:
A-76NG
Repair
(2) NGCheck the following connector:
A-76NG
Repair
Measure at the ABS-ECU connector
B-24.

Disconnect the connector, and
measure at the harness side
connector.

Start the engine.

Voltage between 13 and body
ground
OK:Battery voltageNGCheck the following connectors:
B-24, B-52, B-74, B-76NG
Repair

ABS – TroubleshootingABS – Troubleshooting35B-6
Code No. 27: AYC monitor system (defective AYC)Probable cause
This code is output when the AYC monitor signal becomes faulty.
Defective AYC-ECU

Defective ABS-ECU

Defective harness or connector
OK
Replace the ABS-ECU.
OK
MUT-II data list
AYC signal
OKOFF to be displayed when the
engine runs at idle with the
vehicle stationary.NGReplace AYC-ECU.
OK
Check the harness between ABS-ECU
and AYC-ECU.NG
Repair
Check the following connectors:
B-25, B-96NG
Repair
Code No. 32: Acceleration sensor (longitudinal accelera-
tion) circuit systemProbable cause
This code is output under either of the following conditions:

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

The acceleration sensor (longitudinal acceleration) harness is open- or
short-circuited.
Defective acceleration sensor (longitudinal accelera-
tion)

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 (longitudinal
acceleration) and ABS-ECU.
OK
Check the trouble symptom.NGCheck and repair the harness between
general-purpose fuse No. 6 and
acceleration sensor (longitudinal
acceleration).
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 4 and 17
OK:2.4 – 2.6 V
(horizontal position)NGCheck the following connectors:
B-24, D-20, B-52NG
Repair
NG
Check the harness between accelera-
tion sensor (longitudinal acceleration)
and ABS-ECU.NG
Repair
OK
Check the trouble symptom.
OK
Check the valve relay.NG
Replace
(1) NGCheck the following connectors:
D-20, B-49, B-75NG
Repair
Check the following connector:
D-20, B-49, B-75NG
Repair
(2) NG
Measure at D-20 acceleration sensor
(longitudinal 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-7
Code No.33: Stop lamp switch system (open circuit or
stop lamp stays ON)Probable cause
This code is output, if the stop lamp switch is continuously on for 15 minutes or
more.
Malfunction of stop lamp switch

Malfunction of wiring harness or connector

Malfunction of ABS-ECU
OK
Check the trouble symptom.NGCheck the harness wire, and repair
if necessary.

Between dedicated fuse No. 11
and ABS-ECU
OK
Check the trouble symptom.NGReplace the ABS-ECU.
OK
Check the trouble symptom.NGCheck the harness wire, and repair
if necessary.

Between stop lamp switch and
ABS-ECU
OK
Check the following connectors:
B-15, B-21, B-25, B-32, B-65NG
Repair
OK
Check the following connector:
B-25NG
Repair
YES
Measure at the ABS-ECU connector
B-25.

Disconnect the connector, and
measure at the harness side
connector.

Stop lamp switch: ON

Voltage between 34 and body
ground
OK:Battery voltageNG
Check the following connectors:
B-25, B-32, B-65NG
Repair
OK
Stop lamp switch checkNG
Repair
Does the stop lamp turn on and off
normally?NOStop lamp switch installation checkNG
Repair
Code No. 41, 42, 43, 44: Solenoid valve systemProbable cause
ABS-ECU monitors the solenoid valve energization circuit at all times. This code is
output when no current flows through the solenoid even when ABS-ECU energizes
it or when current continues flowing through the solenoid even when ABS-ECU
deenergizes it, which is considered to be attributable to an open- or short-circuited
solenoid coil or open- or short-circuited harness.
Defective hydraulic unit

Defective harness or connector

Defective ABS-ECU
OK
Replace the ABS-ECU.
OK
Check the trouble symptom.NGCheck the harness between hydraulic
unit (solenoid valve) and ABS-ECU.NG
Repair
OK
Check the trouble symptom.NGCheck and repair the harness between
hydraulic unit and valve relay.
OK
Check the following connectors:
A-21, B-24, B-25NG
Repair
OK
Measure at A-22 hydraulic unit connec-
tor and A-76 valve relay connector.

Disconnect the connector and
measure at the harness side.

Continuity across the following
terminals
Hydraulic Valve relay
unit side side
11–3
OK:Battery voltageNGCheck the following connectors:
A-22, A-76NG
Repair
Check the solenoid valve.NGReplace the hydraulic unit.

ABS – Troubleshooting35B-8
Code No. 51: Valve relay systemProbable cause
This code is output under any of the following conditions:

The solenoid valve power is not supplied when ABS-ECU attempts to turn ON
the valve relay as part of the initial check when the ignition switch is turned ON.

The solenoid valve power remains supplied when ABS-ECU attempts to turn OFF
the valve relay as part of the initial check when the ignition switch is turned ON.

The solenoid valve power is not supplied while the valve relay remains ON under
normal conditions.
Defective ABS valve relay

Defective harness or connector

Defective ABS-ECU
NOTE
In the diagnosis code reading by means of the ABS warning lamp, this code is output in addition to
the actual diagnosis code since the valve relay connector is disconnected.
If the ABS warning lamp turns ON even when the spot represented by the diagnosis code output in
addition to this code has been repaired, and if no diagnosis code other than No. 51 is output, then
the valve relay system is probably defective. Make the following checks.
OK
Check the trouble symptom.NGCheck and repair the harness between
general-purpose fuse No. 6 and valve
relay.
NG
Replace the ABS-ECU.
OK
Check the trouble symptom.
OK
Check the trouble symptom.NGCheck and repair the harness between
valve relay and ABS-ECU.
OK
Check the following connectors:
A-76, B-25NG
Repair
OK
Measure at A-76 valve relay connector
and B-25 ABS-ECU connector.

Disconnect the connector and
measure at the harness side.

Continuity across the following
terminals
OK:Conducting
Valve relay ABS-ECU
side side
3–48
5–37NGCheck the following connectors:
A-76, B-25NG
Repair
OK
Check the trouble symptom.NGCheck and repair the harness between
fusible link No. 8 and valve relay.
OK
Measure at A-76 valve relay connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON
(1) Voltage across 6 and body ground
(2) Voltage across 2 and body ground
OK:Battery voltage(1) NGCheck the following connector:
A-76NG
Repair
(2) NG
Check the following connector:
A-76NG
Repair
Check the valve relay.NG
Replace