Mitsubishi Lancer Evolution IX. Manual - part 622

52B-1

GROUP 52B

SUPPLEMENTAL

 

RESTRAINT 

SYSTEM (SRS)

CONTENTS

GENERAL INFORMATION . . . . . . . .

52B-2

SERVICE PRECAUTIONS. . . . . . . . .

52B-3

SPECIAL TOOLS. . . . . . . . . . . . . . . .

52B-6

TEST EQUIPMENTS . . . . . . . . . . . . .

52B-8

TROUBLESHOOTING . . . . . . . . . . . .

52B-8

POST-COLLISION DIAGNOSIS  . . . .

52B-102

INDIVIDUAL COMPONENT 

 

SERVICE  . . . . . . . . . . . . . . . . . . . . . .

52B-105

WARNING/CAUTION LABELS . . . . .

52B-106

FRONT IMPACT SENSORS  . . . . . . .

52B-107

REMOVAL AND INSTALLATION . . . . . . . . 

52B-107

INSPECTION  . . . . . . . . . . . . . . . . . . . . . . . 

52B-108

SRS CONTROL UNIT (SRS-ECU) . . .

52B-109

REMOVAL AND INSTALLATION  . . . . . . . . 

52B-109

INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . 

52B-110

DRIVER'S AND PASSENGER'S (FRONT) 

 

AIR BAG MODULES AND CLOCK 

 

SPRING. . . . . . . . . . . . . . . . . . . . . . . .

52B-110

REMOVAL AND INSTALLATION  . . . . . . . . 

52B-110

INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . 

52B-115

SEAT BELTS WITH PRE-

 

TENSIONER . . . . . . . . . . . . . . . . . . . .

52B-117

REMOVAL AND INSTALLATION  . . . . . . . . 

52B-117

INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . 

52B-119

AIR BAG MODULE AND SEAT BELT 
PRE-TENSIONER DISPOSAL 

 

PROCEDURES . . . . . . . . . . . . . . . . . .

52B-120

WARNING

•

Carefully read and observe the information in the SERVICE PRECAUTIONS prior to any service.

•

For information concerning troubleshooting or maintenance, always observe the procedures in the 

Troubleshooting section.

•

If any SRS components are removed or replaced in connection with any service procedures, be sure to follow the 

procedures in the INDIVIDUAL COMPONENT SERVICE section for the comportments involved.

•

If you have any questions about the SRS, please contact your local distributor.

GENERAL INFORMATION

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-2

GENERAL INFORMATION

M1524000100558

The Supplemental Restraint System (SRS) and seat 
belt with pre-tensioner is designed to supplement the 
driver's and front passenger's seat belts to help 
reduce the risk or severity of injury to the driver and 
front passenger by activating and deploying both 
front air bags in certain frontal collisions.
The SRS consist of two air bag modules, SRS air 
bag control unit (SRS-ECU), two front impact sen-
sors, SRS warning lamp, clock spring and seat belt 
pre-tensioner. Front air bags are located in the centre 
of the steering wheel and above the glove box. Each 
air bag is made up of a folded air bag and an inflator 
unit. The SRS-ECU under the front floor console 

monitors the system and has a safing G-sensor and 
analogue G-sensor. The warning lamp on the instru-
ment panel indicates the operational status of the 
SRS. The clock spring is installed in the steering col-
umn. The seat belt pre-tensioner is built into the 
driver's and passenger's front seat belt retractor. The 
front impact sensor is assembled on the headlamp 
support panel to monitor collision upon frontal 
impact.
Only authorized service personnel should do work on 
or around the SRS components. Those service per-
sonnel should read this manual carefully before start-
ing any such work.

AC310783

AC304668

AC310070

AC208855

Driver's air bag 
module

Clock spring

Passenger's (front) 
air bag module

SRS-ECU

Diagnosis connector

SRS warning lamp

Seat belt with 
pre-tensioner

Front impact sensor 

AB

SERVICE PRECAUTIONS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-3

SERVICE PRECAUTIONS

M1524000300596

DANGER

In order to avoid injury to yourself or others 
from accidental deployment of the air bag 
during servicing, read and carefully follow all 
the precautions and procedures described in 
this manual.

CAUTION

Do not use any electrical test equipment on or 
near SRS components, except those specified on 

P.52B-8

.

CAUTION

Never Attempt to Repair the Following Compo-
nents:

1. SRS air bag control unit (SRS-ECU)
2. Clock spring
3. Driver's and front passenger's (front) air bag 

modules

4. Front impact sensor
5. Seat belt with pre-tensioner

NOTE: If any of these components are diagnosed as 
faulty, they should only be replaced, in accordance 
with the INDIVIDUAL COMPONENTS SERVICE pro-
cedures in this manual, starting at page 

P.52B-105

.

CAUTION

AC300634

SRS-ECU connector

AB

SERVICE PRECAUTIONS

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-4

Do not attempt to repair the wiring harness con-
nectors of the SRS. If a defective wiring harness 
is found, repair or replace it by referring to the 
table below.

SRS-ECU terminal No.

Destination of harness

Remedy

1, 2

Instrument panel wiring harness 

→ 

Front wiring harness (RH) 

→ Front 

impact sensor (RH)

Correct or replace each wiring 
harness.

3, 4

Instrument panel wiring harness 

→ 

Front wiring harness (LH) 

→ Front 

impact sensor (LH)

Correct or replace each wiring 
harness.

7

Instrument panel wiring harness

→ 

Earth

Correct or replace the instrument 
panel wiring harness.

8

Instrument panel wiring harness 

→ 

SRS warning lamp

Correct or replace the instrument 
panel wiring harness.

9, 10

Instrument panel wiring harness 

→ 

Passenger's (front) air bag module

Correct or replace the instrument 
panel wiring harness.

11, 12

Instrument panel wiring harness 

→ 

Clock spring 

→ Driver's air bag 

module

Correct or replace instrument panel 
wiring harness. Replace the clock 
spring.

13

Instrument panel wiring harness 

→ 

Junction block (fuse No.3)

Correct or replace the instrument 
panel wiring harness.

16

Instrument panel wiring harness 

→ 

Junction block (fuse No.2)

Correct or replace the instrument 
panel wiring harness.

20

Instrument panel wiring harness 

→ 

Diagnosis connector

Correct or replace the instrument 
panel wiring harness.

27, 28

Floor wiring harness (RH) 

→ 

Passenger's (front) seat belt 
pre-tensioner <LH drive vehicles> 
Floor wiring harness (LH) 

→ 

Passenger's (front) seat belt 
pre-tensioner <RH drive vehicles>

Connect or replace the floor wiring 
harness.

29, 30

Floor wiring harness (LH) 

→ Driver's 

seat belt pre-tensioner <LH drive 
vehicles> Floor wiring harness (RH) 
→ Driver's seat belt pre-tensioner 
<RH drive vehicles>

Connect or replace the floor wiring 
harness.