Mitsubishi Montero (2004+). Manual - part 1004

HYDRAULIC BRAKE BOOSTER (HBB) DIAGNOSIS

TSB Revision

BASIC BRAKE SYSTEM

35A-15

1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System select."
5. Choose "HBB" from the "CHASSIS" tab.
6. Select "MITSUBISHI."
7. Select "Diagnostic Trouble Code."
8. If a DTC is set, it is shown.
9. Choose "Erase DTCs" to erase the DTC.

HOW TO READ DATA LIST

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

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. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System select."
5. Choose "HBB" from the "CHASSIS" tab.
6. Select "MITSUBISHI."
7. Select "Data List."
8. Choose an appropriate item and select the "OK" button.

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR

HYDRAULIC BRAKE BOOSTER (HBB) DIAGNOSIS

TSB Revision

BASIC BRAKE SYSTEM

35A-16

HOW TO PERFORM ACTUATOR TEST

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

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. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System select."
5. Choose "HBB" from the "CHASSIS" tab.
6. Select "MITSUBISHI."
7. Select "Actuator Test."
8. Choose an appropriate item and select the "OK" button.

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR

HYDRAULIC BRAKE BOOSTER (HBB) DIAGNOSIS

TSB Revision

BASIC BRAKE SYSTEM

35A-17

DIAGNOSTIC TROUBLE CODE CHART

M1351013700066

Follow the inspection chart that is appropriate for the 
diagnostic trouble code.

NOTE: If the trouble marked by * has occurred, the M-ASTC-ECU sounds the buzzer continuously to inform 
the trouble of the driver and protects the pump motor by activating the pump motor intermittently.

DTC

INSPECTION ITEM

DIAGNOSTIC CONTENT

REFERENCE PAGE

16

Battery positive voltage

M-ASTC-ECU power supply voltage is 
extremely low or high

P.35A-18

31

Ignition switch circuit

Open circuit at the HBB power supply 
sub circuit

P.35A-20

53

Pump motor

• Seizure of the pump motor*

• Abnormality at the current detection 

circuit of the M-ASTC-ECU

P.35A-25

54

Motor relay

Open circuit, short circuit or failure of the 
motor relay coil

P.35A-33

55

Pump motor circuit

Pump motor energized abnormally for 
long period*

P.35A-58

56

Pressure switch

• Open circuit at the pressure switch (for 

pump motor control)

• Open circuit or short circuit at the 

pressure switch (for low-pressure 
warning)

P.35A-71

57

Accumulator

Accumulator low-pressure abnormality*

P.35A-79

58

M-ASTC-ECU (Power 
supply drive circuit)

Pump motor drive circuit in the 
M-ASTC-ECU abnormality

Replace the 
M-ASTC-ECU (Refer to 
GROUP 35C, 
M-ASTC-ECU 

P.35C-213

).

HYDRAULIC BRAKE BOOSTER (HBB) DIAGNOSIS

TSB Revision

BASIC BRAKE SYSTEM

35A-18

HBB DIAGNOSTIC TROUBLE CODE PROCEDURES

DTC 16: Battery Positive Voltage (M-ASTC-ECU Power Supply Voltage is Extremely Low or High)

CAUTION

If the battery voltage drops or rises while making this check, DTC 16 is set as an existing problem, 
making it impossible to perform correct trouble diagnosis. Before carrying out the following diagno-
sis, test the battery and charge it if necessary.

AC204492AC

ASC-ECU Power Supply Circuit

AC204688 AB

CONNECTOR: D-116

D-116

AC204547AB

CONNECTORS: D-208, D-212

D-208

D-212

JUNCTION BLOCK
(FRONT VIEW)