Mitsubishi Colt Ralliart. Manual — part 244

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-68

COMMENTS ON TROUBLE SYMPTOM

• If the ABS system fails, the ABS-ECU will send a

lamp drive signal to the combination meter
through the CAN communication lines.

• If the combination meter detects a ABS time-out

due to a failure in the power supply to the
ABS-ECU or abnormal CAN communication, the
combination meter illuminates the lamp.

• If the CAN bus communication fails, refer to

GROUP 54D, CAN Bus Diagnostics Table

P.54D-13

• If a trouble occurs in the power supply to the

ABS-ECU (i.e. excessively high resistance in the
power supply or earth lines), this trouble symp-
tom will appear., but the diagnosis code will not
be set. Then, if you drive the vehicle at 6 km/h or
more, the ECU will set diagnosis code C1861.

• Perform the actuator test to extinguish the lamp

in the combination meter. If it does not extinguish,
replace the combination meter. If it extinguishes,
replace the ABS-ECU.

• It is also suspected that the combination meter

does not obey the commands from the
ABS-ECU. If the combination meter does not
function after the ABS-ECU is replaced, replace
the combination meter.

POSSIBLE CAUSES

• Damaged harness wires and connectors

• Defective combination meter (incorporating the

meter-ECU)

• The ABS-ECU is defective.

• The power supply circuit is defective.

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics

CAUTION

Before connecting or disconnecting the
M.U.T.-III, turn the ignition switch to the "LOCK"
(OFF) position.
(1) Connect M.U.T.-III to the 16-pin diagnosis

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF)

position.

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the CAN bus line (Refer to GROUP
54D, Diagnosis

P.54D-13

AC206895

Diagnosis

connector

MB991827

MB991824

MB991910

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-69

STEP 2. M.U.T.-III diagnosis code

CAUTION

Before connecting or disconnecting the
M.U.T.-III, turn the ignition switch to the "LOCK"
(OFF) position.
(1) Connect M.U.T.-III to the 16-pin diagnosis

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Check whether the ABS-related diagnosis code is

set.

(4) Turn the ignition switch to the "LOCK" (OFF)

position.

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Carry out the diagnosis for the diagnosis
code (Refer to

P.35B-7

STEP 3. M.U.T.-III diagnosis code

CAUTION

Before connecting or disconnecting the
M.U.T.-III, turn the ignition switch to the "LOCK"
(OFF) position.
(1) Connect M.U.T.-III to the 16-pin diagnosis

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Drive the vehicle at 10 km/h or more. Then use

the M.U.T.-III to check whether the ABS
diagnosis code is reset.

(4) Turn the ignition switch to the "LOCK" (OFF)

position.

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Carry out the diagnosis for the diagnosis
code (Refer to

P.35B-7

AC206895

Diagnosis

connector

MB991827

MB991824

MB991910

AC206895

Diagnosis

connector

MB991827

MB991824

MB991910

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-70

STEP 4. M.U.T.-III actuator test

CAUTION

Before connecting or disconnecting the
M.U.T.-III, turn the ignition switch to the "LOCK"
(OFF) position.
(1) Connect M.U.T.-III to the 16-pin diagnosis

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Execute combination meter actuator test.

• Item A1: Indicator lamp and warning lamp

(extinguish)

(4) Turn the ignition switch to the "LOCK" (OFF)

position.

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

Q: Does the ABS warning lamp extinguish normally?

YES : .

Replace the combination meter (integrated

with meter-ECU) (Refer to GROUP 54A,
Combination Meter

P.54A-67

). Then go to

Step 5.

NO : .

Replace the hydraulic unit (integrated with

ABS-ECU) (Refer to

P.35B-78

STEP 5. Recheck the trouble symptom.

Q: Does the ABS warning lamp extinguish after the

engine has been started?
YES :

This diagnosis is complete.

NO :

Replace the combination meter (integrated
with meter-ECU) (Refer to GROUP 54A,
Combination Meter

P.54A-67

AC206895

Diagnosis

connector

MB991827

MB991824

MB991910

Main

Index

Group

TOC

TROUBLESHOOTING

ANTI-SKID BRAKING SYSTEM (ABS)

35B-71

Inspection Procedure 5: The ABS operates too frequently (no diagnosis code is set)

COMMENTS ON TROUBLE SYMPTOM

• This trouble symptom will not appear due to a

failure in wiring harness (open or short circuit, or
excessive resistance). Therefore, if the sensors
are installed properly and the check result does
not indicate any problems, replace the ABS-ECU.

POSSIBLE CAUSES

• Wheel speed sensor malfunction

• Hub malfunction

• ABS-ECU malfunction

DIAGNOSIS PROCEDURE

STEP 1. Check the wheel speed sensors for
proper installation.
Check that the wheel speed sensors are installed
correctly (e.g. loosely tightened bolts).

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Reinstall the wheel speed sensor(s)
properly.

STEP 2. Remove the wheel speed sensors and
check them.
Refer to

P.35B-81

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Replace the wheel speed sensor (Refer to