Mitsubishi Montero (2004+). Manual — part 1045

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-23

DTC 21, 22, 23, 24: ABS Sensor

AC204644AB

ABS Sensor Circuit

AC000709AF

CONNECTOR: A-03

AC000710

CONNECTOR: A-24

AJ

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

TSB Revision

ANTI-LOCK BRAKING SYSTEM (ABS)

35B-24

.

CIRCUIT OPERATION

• A toothed ABS rotor generates a voltage pulse as

it moves across the pickup field of each ABS sen-
sor.

• The amount of voltage generated at each wheel

is determined by the clearance between the ABS
rotor teeth and the ABS sensor, and by the speed
of rotation.

• The ABS sensors transmit the frequency of the

voltage pulses and the amount of voltage gener-
ated by each pulse to the Mitsubishi active skid
and traction control system-electronic control unit
(M-ASTC-ECU).

• The ABS hydraulic unit modulates the amount of

braking force individually applied to each wheel
cylinder.

.

ABS DTC SET CONDITIONS
DTCs 21, 22, 23, 24 are output in the following
cases:

• Open circuit is not found but no input is received

by one or more of the four ABS sensors at 10
km/h (6 mph) or more.

• Sensor output drops due to a malfunctioning sen-

sor or warped ABS rotor.

.

TROUBLESHOOTING HINTS
The most likely causes for these DTCs to set are:

• Malfunction of the ABS sensor

• Damaged wiring harness and connector

• Malfunction of the M-ASTC-ECU

• Malfunction of the ABS rotor

• Malfunction of the wheel bearing

• Excessive clearance between the sensor and

ABS rotor

.

AC000711

CONNECTOR: A-37

AF

ACX02283

CONNECTOR: D-111

AD

ACX01852

E-110

CONNECTORS: E-105, E-110

AM

E-105

ACX02289AK

CONNECTOR: F-11

ACX02290

CONNECTORS: G-14, G-21

AE

G-14

G-21

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

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ANTI-LOCK BRAKING SYSTEM (ABS)

35B-25

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

• MB991223: Harness Set

STEP 1. Using scan tool MB991958, check data list.

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Start the engine.

(3) Set scan tool MB991958 to the data reading mode, and

check the data list items by driving the vehicle.

• Item 11 (DTC 21 is set): Front right wheel speed sensor

• Item 12 (DTC 22 is set): Front left wheel speed sensor

• Item 13 (DTC 23 is set): Rear right wheel speed sensor

• Item 14 (DTC 24 is set): Rear left wheel speed sensor

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Does the speedometer indication match the scan tool

indication?
YES : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

− How to

Cope with Intermittent Malfunction

P.00-6

.

NO : Go to Step 2.

AC307591 AB

MB991911

DATA LINK

CONNECTOR

MB991824

MB991827

ANTI-LOCK BRAKING SYSTEM (ABS) DIAGNOSIS

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ANTI-LOCK BRAKING SYSTEM (ABS)

35B-26

STEP 2. Check the ABS sensor installation.

Q: Is the ABS sensor bolted securely in place at the front

knuckle or the rear knuckle?
YES : Go to Step 3.
NO : Install it properly. Refer to

P.35B-129

. Then go to Step

11.

STEP 3. Inspect the ABS sensor or ABS rotor.

Refer to

P.35B-130

.

Check items:

• ABS sensor internal resistance: 1.0 − 1.5 kΩ

• Insulation between the ABS sensor body and the connector

terminals

• Toothed ABS rotor check

Q: Is the ABS sensor or ABS rotor damaged?

YES : Replace it and then go to Step 11.
NO : Go to Step 4.

ACX01221

ABS SENSOR <FRONT>

AD

ACX01227AD

ABS SENSOR <REAR>