Mitsubishi Colt Ralliart. Manual — part 230

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-12

(2) Resistance between ABS-ECU connector A-05

terminal 6 and front right wheel speed sensor
A-29 terminal 1

OK: 10

Ω or less

(3) Resistance between ABS-ECU connector A-05

terminal 7 and front right wheel speed sensor
A-29 terminal 2

OK: 10

Ω or less

Q: Is the check result normal?

YES :

Go to Step 5.

NO :

Repair the wiring harness between
ABS-ECU connector A-05 and front right
wheel speed sensor connector A-29.

STEP 5. Check whether the diagnosis code is
reset.

CAUTION

Before connecting or disconnecting the
M.U.T.-III, turn the ignition switch to the "LOCK"
(OFF) position.
Check again if the diagnosis code is set.
(1) Turn the ignition switch to the "ON" position.
(2) Erase the diagnosis code.
(3) Turn the ignition switch to the "LOCK" (OFF)

position.

(4) Turn the ignition switch to the "ON" position.
(5) Check if the diagnosis code is set.
(6) Turn the ignition switch to the "LOCK" (OFF)

position.

(7) Disconnect M.U.T.-III.

Q: Is code No.C1200 set?

YES :

Replace the hydraulic unit (integrated with

ABS-ECU) (Refer to

P.35B-78

).

NO :

The malfunction is intermittent. Refer to
GROUP 00, How to Use
Troubleshooting/Inspection Service Points

−

How to Cope with Intermittent Malfunction

P.00-13

.

AC314250

AC314250AB

MB991951

Check
connector

ABS-ECU

A-05 Harness connector

Connector A-29
(Harness side)

AC314250AC

MB991951

Check
connector

ABS-ECU

A-05 Harness connector

Connector A-29
(Harness side)

AC206895

AC

Diagnosis

connector

MB991827

MB991824

MB991910

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-13

Code No.C1201: Wheel speed sensor (FR) system (sensor output failure)

OPERATION

The wheel speed sensor is a pulse generator. It con-
sists of encoder (a plate on which north and south
pole sides of the magnets are arranged alternately)
for detecting wheel speed which rotates at the same
speed as the road wheels. This sensor sends fre-
quency pulse signals in proportion to wheel speed.
The pulse signals, which the wheel speed sensor
creates, are sent to the ABS-ECU. The ABS-ECU
uses the frequency of the pulse signals to determine
the wheel speed.

DIAGNOSIS CODE SET CONDITIONS

The ABS-ECU monitors the signals from the wheel
speed sensors during driving. If the ECU detects
malfunctions below, it sets the diagnosis code.

• Missing of wheel speed sensor signals

• When an abnormal wheel speed sensor signal is

received

• When one of the wheel speed sensor signals

(from the front, rear, right and left wheels) is sig-
nificantly different from the others

PROBABLE CAUSES

• Improperly installed wheel speed sensor

• Presence of dirt or other foreign particles on the

encoder of the wheel speed sensor

• Deformed encoder of the wheel speed sensor

• Excessive gap between the wheel speed sensor

and its encoder

• Damaged wiring harness or connector

• Malfunction of the wheel speed sensor

• Malfunction of the hydraulic unit (integrated with

ABS-ECU)

FRONT WHEEL SPEED SENSOR

(LH)

(RH)

(LH)

(RH)

ABS-ECU

REAR WHEEL SPEED SENSOR

Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Gray R : Red P : Pink V : Violet

Wheel Speed Sensor Circuit

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-14

DIAGNOSIS PROCEDURE

STEP 1. Connector check: A-29 front right wheel
speed sensor connector

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the defective connector.

STEP 2. Remove the front right wheel speed
sensor and check it.
Refer to

P.35B-81

.

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Replace the front right wheel speed sensor
(Refer to

P.35B-80

).

STEP 3. Check the wheel bearing for excessive
play.
Front: refer to GROUP 26, On-vehicle Service

−

Wheel Bearing Axial Play Check

P.26-5

.

Rear: refer to GROUP 27, On-vehicle Service

−

Wheel Bearing Axial Play Check

P.27-3

.

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Replace the hub assembly (Refer to
GROUP 26, Front Axle Hub Assembly

P.26-6

).

STEP 4. Check the encoder for detecting wheel
speed.
Check the encoder for presence of foreign objects or
deformation.

Q: Is the check result normal?

YES :

Go to Step 5.

NO :

If foreign objects are found, clean the
encoder. If deformation is found, replace the
hub (Refer to GROUP 26, Front Axle Hub
Assembly

P.26-9

).

STEP 5. Check whether the diagnosis code is
reset.

CAUTION

Before connecting or disconnecting the
M.U.T.-III, turn the ignition switch to the "LOCK"
(OFF) position.
Check again if the diagnosis code is set.
(1) Turn the ignition switch to the "ON" position.
(2) Erase the diagnosis code.
(3) Turn the ignition switch to the "LOCK" (OFF)

position.

(4) Turn the ignition switch to the "ON" position.
(5) Check if the diagnosis code is set.
(6) Turn the ignition switch to the "LOCK" (OFF)

position.

(7) Disconnect M.U.T.-III.

Q: Is code No.C1201 set?

YES :

Replace the hydraulic unit (integrated with

ABS-ECU) (Refer to

P.35B-78

).

NO :

The malfunction is intermittent. Refer to
GROUP 00, How to Use
Troubleshooting/Inspection Service Points

−

How to Cope with Intermittent Malfunction

P.00-13

.

AC313860AF

Connector : A-29

A-29(B)

Harness side

AC206895

AC

Diagnosis

connector

MB991827

MB991824

MB991910

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-15

Code No.C1205: Wheel speed sensor (FL) system (open circuit, short to earth or power supply)

OPERATION

The wheel speed sensor is a pulse generator. It con-
sists of encoder (a plate on which north and south
pole sides of the magnets are arranged alternately)
for detecting wheel speed which rotates at the same
speed as the road wheels. This sensor sends fre-
quency pulse signals in proportion to wheel speed.
The pulse signals, which the wheel speed sensor
creates, are sent to the ABS-ECU. The ABS-ECU
uses the frequency of the pulse signals to determine
the wheel speed.

DIAGNOSIS CODE SET CONDITIONS

The ABS-ECU monitors the voltage change in each
of the wheel speed sensor circuits. If the ECU
detects an open or short circuit in any of the circuits,
the ECU sets the diagnosis code.

PROBABLE CAUSES

• Damaged wiring harness or connector

• Malfunction of the wheel speed sensor

• Malfunction of the hydraulic unit (integrated with

ABS-ECU)

FRONT WHEEL SPEED SENSOR

(LH)

(RH)

(LH)

(RH)

ABS-ECU

REAR WHEEL SPEED SENSOR

Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Gray R : Red P : Pink V : Violet

Wheel Speed Sensor Circuit

Main

Index

Group

TOC