Mitsubishi Montero (2002-2004). Manual — part 1021

HYDRAULIC BRAKE BOOSTER (HBB) DIAGNOSIS

TSB Revision

BASIC BRAKE SYSTEM

35A-109

• The wire between buzzer connector E-107 (terminal 2) and

transfer-ECU connector E-104 (terminal 51)

NOTE: Also check intermediate connector E-114 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If intermediate connector E-114 is damaged,
repair or replace the damaged component(s) as described in
GROUP 00E, Harness Connector Inspection

P.00E-2

. If the

connector has been repaired or replaced, go to Step 5.

Q: Is the harness wire damaged?

YES : Repair or replace it and then go to Step 5.
NO : Replace the buzzer (Refer to

P.35A-139

). Then go to

Step 5.

AC204727AB

CONNECTOR: E-107

E-107

HARNESS
CONNECTOR:
COMPONENT
SIDE

E-107

AC204728 AB

CONNECTOR: E-104

E-104

HARNESS CONNECTOR:
COMPONENT SIDE

E-104

AC204548AN

CONNECTOR: E-114

E-114

HYDRAULIC BRAKE BOOSTER (HBB) DIAGNOSIS

TSB Revision

BASIC BRAKE SYSTEM

35A-110

STEP 5. Retest the system.

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Using scan tool MB991502, check actuator test and sound

the buzzer.

Q: Does the buzzer sound for three seconds and then

stop?
YES : The procedure is complete.
NO : Start over at Step 1.

DATA LIST REFERENCE TABLE

M1352011500412

The following items can be read by the scan tool
from the M-ASTC-ECU input data.

ACTUATOR TEST REFERENCE TABLE

M1351013500051

The scan tool activates the following actuators for
testing.

NOTE:

.

•

If the M-ASTC-ECU is inoperative, actuator test-
ing cannot be carried out.

•

Actuator testing is only possible when the vehicle
is stationary.

ACX01539

16-PIN

MB991502

AC

MUT-II SCAN
TOOL DISPLAY

ITEM
NO.

CHECK ITEM

CHECKING REQUIREMENT

NORMAL
CONDITION

BATT.
VOLTAGE

31

M-ASTC-ECU
power supply
voltage

Ignition switch: ON

6.5

− 22.3 V

ACCUM SW
(PL)

76

Pressure switch (for
low-pressure
warning)

Ignition switch: ON

ON

ACCUM SW
(PH)

77

Pressure switch (for
pump motor control)

Ignition switch: ON When the pump motor

is not operating.

OFF

When the pump motor
is operating.

ON

MOTOR RLY

79

Motor relay A, B

Ignition switch: ON When the pump motor

is not operating.

OFF

When the pump motor
is operating.

ON

HYDRAULIC BRAKE BOOSTER (HBB) DIAGNOSIS

TSB Revision

BASIC BRAKE SYSTEM

35A-111

CHECK AT M-ASTC-ECU

M1351013600069

Terminal Voltage Check Chart

NOTE: Do not measure terminal voltage during the approxi-
mately three seconds after the ignition switch is turned to the
"ON" position. The M-ASTC-ECU performs the initial check
during that period.
Measure the voltage between terminal (4), (22), (56) or (64)
(ground terminals) and each respective terminal by
backprobing.

MUT-II SCAN
TOOL DISPLAY

NO.

ITEM

DRIVE CONTENT

Activation when the system fails

HBB MOTOR

11

Pump motor

Drives the pump motor
for one second.

Disabled

HBB BUZZER

12

Buzzer

Drives the buzzer for
three seconds.

Disabled

BRKE WARN LMP 23

Brake warning
light

Illuminates the brake
warning light.

Enabled (However, disabled when
the brake warning light can not be
activated)

AC203901

AC204627AT

M-ASTC-ECU

M-ASTC-ECU CONNECTORS

TERMINAL NO.

SIGNAL

CHECKING REQUIREMENT

NORMAL
CONDITION

9

M-ASTC-ECU
power supply

Ignition switch: ON

Battery positive
voltage

11

Pressure switch
(Pump motor
control)

Ignition switch:
ON

Brake fluid pressure: LOW
(Pump motor operates.)

Approximately 6V

Brake fluid pressure: HIGH
(Pump motor does not operate.)

Less than 2V

HYDRAULIC BRAKE BOOSTER (HBB) DIAGNOSIS

TSB Revision

BASIC BRAKE SYSTEM

35A-112

Resistance and Continuity between Harness
Connector Terminals

1. Turn the ignition switch to the "LOCK" (OFF) position and

disconnect the M-ASTC-ECU connectors.

12

Pump motor
current detection
(

−)

Ignition switch: ON

Less than 2V

14

Pump motor
current detection
(+)

Ignition switch:
ON

Pump motor does not operate.

Less than 2V

Pump motor operates.

Battery positive
voltage

24

Motor relay B

Ignition switch:
ON

Pump motor does not operate.

Battery positive
voltage

Pump motor operates.

Less than 2V

25

Pump motor
monitor

Ignition switch: ON

Less than 2V

48

Motor relay A

Ignition switch:
ON

Pump motor does not operate.

Battery positive
voltage

Pump motor operates.

Less than 2V

54

Buzzer

Ignition switch:
ON

Buzzer does not sound.

Battery positive
voltage

Buzzer sounds.

Less than 2V

57

Pressure switch
(low-pressure
warning)

Ignition switch:
ON

Brake fluid pressure: EXTRA
LOW
(Buzzer sounds.)

Approximately 9V

Brake fluid pressure: NORMAL
(Buzzer does not sound.)

Approximately 4V

63

M-ASTC-ECU
power supply

Ignition switch: ON

Battery positive
voltage

81

Brake warning
light

Engine: Idling

The warning light does not
illuminate.

Less than 2V

The warning light illuminates.

Battery positive
voltage

TERMINAL NO.

SIGNAL

CHECKING REQUIREMENT

NORMAL
CONDITION