Mitsubishi Montero (2002-2004). Manual - part 1022

HYDRAULIC BRAKE BOOSTER (HBB) DIAGNOSIS

TSB Revision

BASIC BRAKE SYSTEM

35A-113

2. Measure the resistance between the terminals of the 

harness connector (component side). The terminals to be 
checked are indicated in the table below.

TERMINAL NO.

SIGNAL

NORMAL 
CONDITION

22 

− body ground

Ground 1

Less than 2 ohms

4 

− body ground

Ground 2

Less than 2 ohms

56 

− body ground

Ground 3

Less than 2 ohms

64 

− body ground

Ground 4

Less than 2 ohms

AC203901

AC204627AU

M-ASTC-ECU

HARNESS CONNECTORS: 

COMPONENT SIDE

SPECIAL TOOLS

TSB Revision

BASIC BRAKE SYSTEM

35A-114

SPECIAL TOOLS

M1351000600230

TOOL

TOOL NUMBER AND 
NAME

SUPERSESSION

APPLICATION

MB991502
Scan tool (MUT-II)

MB991496-OD

• For checking of HBB 

[Diagnostic trouble code 
display when using the scan 
tool (MUT-II)]

• Air bleeding of ABS system 

in HBB system

MB991529
Diagnostic trouble code 
check harness

Tool not necessary 
if scan tool (MUT-
II) is available.

For checking of HBB [Diagnostic 
trouble code display when using 
the brake warning light]

MB991223
Harness set
A: MB991219
Inspection harness

MB991223
MB991709-01

For hydraulic brake booster 
(HBB) diagnosis

MB991926
Accumulator wrench

−

Accumulator removal and 
installation

MB991620
Valve spring compressor 
adapter

−

Fixing of HBB

MB990964
Brake tool set
A: MB990520
Disc brake piston expander

General service 
tool

Pushing-in of the disc brake 
piston

B991502

MB991529

MB991223

A

AB

B

C

D

MB991926

MB991620

MB990964

A

B

B

ON-VEHICLE SERVICE

TSB Revision

BASIC BRAKE SYSTEM

35A-115

ON-VEHICLE SERVICE

BRAKE PEDAL CHECK AND ADJUSTMENT

M1351000900297

Brake Pedal Height

1. Turn up the carpet etc. under the brake pedal.
2. Measure the brake pedal height as illustrated.

Standard value: 192 

− 195 mm (7.6 − 7.7 inches)

3. If the brake pedal height is not within the standard value, 

adjust as follows.

(1) Disconnect the stoplight switch connector.
(2) Rotate the stoplight switch 1/4 turn counterclockwise to 

loosen.

(3) Loosen the operating rod jam nut. Turn the serrations of 

the operation rod with pliers to adjust the brake pedal 
height to the standard value.

(4) Turn the stoplight switch until it contacts the stopper. 

During this step, secure the pedal by moving it forward by 
hand.

(5) Turn the stoplight switch 1/4 turn clockwise to secure, 

and confirm that the clearance between the switch 
plunger and the stopper is as shown.

(6) Connect the connector of the stoplight switch.
(7) Check to be sure that the stoplight does not illuminate 

with the brake pedal released.

4. Check the key interlock and shift lock mechanisms (Refer to 

GROUP 23A, On-vehicle Service 

− Key Interlock and Shift 

Lock Mechanism Check 

P.23Aa-24

).

5. Return the carpet etc. to its original position.

Brake Pedal Free Play

1.  Turn the ignition switch to the "ON" position, and wait until 

the HBB pump motor stops.
NOTE:  If the brake fluid inside the accumulator is not pres-
surized to a predetermined value, the pump motor will start 
to run. Once the pump motor has stopped, the brake fluid 
inside the accumulator is pressurized to the predetermined 
value. If the brake fluid inside the accumulator is pressurized 
to a predetermined value, the pump motor will not start to 
run.

ACX00657AB

OPERATING
ROD LOCK
NUT

STOPLIGHT
SWITCH

OPERATING 
ROD

ACX01815AB

JAM NUT

PEDAL UP

PEDAL 
DOWN

AC101091AB

STOPPER

0.5 - 1.0 mm
(0.02 - 0.04 in)

ON-VEHICLE SERVICE

TSB Revision

BASIC BRAKE SYSTEM

35A-116

2.  Operate the pedal by hand, and check that the pedal stroke 

(free play) meets the standard value at the point where 
resistance is felt.

Standard value: 3 mm (0.1 inch) or less

3. If the brake pedal play is not within the standard value, 

check the following, and adjust or replace if necessary:

• Excessive play between the brake pedal and the clevis pin, 

or between the clevis pin and the brake booster operating 
rod

• Brake pedal height

• Installation position of the stoplight switch, etc.

Clearance between Brake Pedal and Floorboard

1. Turn up the carpet etc. under the brake pedal.
2. Start the engine, depress the brake pedal with 

approximately 500 N (112 pounds) of force, and measure 
the clearance between the brake pedal and the floorboard.

Standard value: 90 mm (3.5 inches) or more

3. If the clearance is outside the standard value, check for air 

trapped in the brake line and thickness of the disc brake 
pad. And then adjust and replace defective parts as 
required.

4. Return the carpet etc. to its original position.

STOPLIGHT SWITCH CHECK

M1351008900213

1. Connect an ohmmeter between the stoplight switch 

connector terminals. 

2. There should be no continuity between the terminals when 

the plunger is pushed in as shown. There should be 
continuity when it is released.

ACX00659

ACX00660

TESTER 
CONNECTION

PLUNGER

SPECIFIED 
CONDITION

1 

− 2

IN

Open circuit

OUT

Less than 2 ohms

ACX00671AB

NO CONTINUITY CONTINUITY

4 mm

(0.16 in)