Mitsubishi Galant 9G. Manual - part 1404

SERVICE PRECAUTIONS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-26

SERVICE PRECAUTIONS

M1524000300499

DANGER

•

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

•

After disconnecting the battery cable, wait 60 sec-
onds or more before proceeding with the following 
work. The SRS system is designed to retain 
enough voltage to deploy the air bag for a short 
time even after the battery has been disconnected, 
so serious injury may result from unintended air 
bag deployment if work is done on the SRS system 
immediately after the battery cables are discon-
nected.

WARNING

•

Battery posts, terminals and related accessories 
contain lead and lead compounds. WASH HANDS 
AFTER HANDLING.

•

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

P.52B-347

.

•

Never Attempt to Repair the Following Compo-
nents: SRS-ECU, Clock Spring, Air Bag Module, 
Front impact sensor, Side Impact Sensor, Seat Belt 
with Pre-tensioner, Seat slide sensor, Front seat 
assenbly. If any of these components are diag-
nosed as faulty, they should only be replaced, in 
accordance with the INDIVIDUAL COMPONENT 
SERVICE procedures in this manual, starting on 

P.52B-353

.

•

Do not attempt to repair the wiring harness con-
nectors of the SRS. If any of the connectors are 
diagnosed as faulty, replace the wiring harness. If 
the wires are diagnosed as faulty, replace or repair 
the wiring harness according to the following 
table.

.

ACX00583

INSULATING TAPE

BATTERY

BATTERY CABLE (–)

AC

63

55

51

69

61

66

58

65

64

56 57

68

60

67

59

70

62

53

52 B

A

54

A

B

18

10

15

7

13

5

14

6

16

8

17

9

19

11

20

12

1 2

3 4

42

31

38

27

21

41

28

39

22

30

25

47

36

33

44

34

45

37

48

26

29

23

40

32

43

35

46

24

B

A

AC3001278AB

SRS-ECU CONNECTOR

SERVICE PRECAUTIONS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-27

SRS-ECU TERMINAL 
NO.

DESTINATION OF HARNESS

CORRECTIVE ACTION

1, 2

Floor wiring harness 

→ Seat slide 

sensor

Correct or replace the floor wiring 
harness.

3

Floor wiring harness 

→ Driver’s seat 

belt switch for N/C terminal

Correct or replace the floor wiring 
harness.

4

Floor wiring harness 

→ Driver’s seat 

belt switch for COM terminal

Correct or replace the floor wiring 
harness.

7, 8

Floor wiring harness 

→ Seat belt 

pre-tensioner (LH)

Correct or replace the floor wiring 
harness.

9*, 10*

Floor wiring harness 

→ Side-airbag 

module (LH)

Correct or replace the floor wiring 
harness.

18

Floor wiring harness 

→ Driver’s seat 

belt switch for N/O terminal

Correct or replace the floor wiring 
harness.

19*, 20*

Floor wiring harness 

→ Side impact 

sensor (LH)

Correct or replace the floor wiring 
harness.

21

Floor wiring harness 

→ Instrument 

panel wiring harness 

→ Air bag off 

indicator light

Correct or replace each wiring harness.

23

Floor wiring harness 

→ Instrument 

panel wiring harness 

→ Junction block 

(fuse No.22)

Correct or replace each wiring harness.

24

Floor wiring harness 

→ Instrument 

panel wiring harness 

→ Junction block 

(fuse No.23)

Correct or replace each wiring harness.

27, 28

Floor wiring harness 

→ Instrument 

panel wiring harness 

→ Air bag module 

(Front passenger's side) <1st squib 
side>

Correct or replace each wiring harness.

30, 31

Floor wiring harness 

→ Instrument 

panel wiring harness 

→ Air bag module 

(Front passenger's side) <2nd squib 
side>

Correct or replace each wiring harness.

32

Can line

Correct or replace can line.

33, 34

Floor wiring harness 

→ Instrument 

panel wiring harness 

→ Clock spring → 

Air bag module (Driver's side) <2nd 
squib side>

Correct or replace each wiring harness. 
Replace the clock spring.

36, 37

Floor wiring harness 

→ Instrument 

panel wiring harness 

→ Clock spring → 

Air bag module (Driver's side) <1st 
squib side>

Correct or replace each wiring harness. 
Replace the clock spring.

38, 39

Floor wiring harness 

→ Instrument 

panel wiring harness 

→ Front wiring 

harness 

→ Front impact sensor (LH)

Correct or replace each wiring harness.

40

Floor wiring harness 

→ Ground

Correct or replace the floor wiring 
harness.

SERVICE PRECAUTIONS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-28

NOTE: *Vehicles with side-airbags

.

42

Floor wiring harness 

→ Instrument 

panel wiring harness 

→ Seat belt 

warning light

Correct or replace each wiring harness.

43

Can line

Correct or replace can line.

47, 48

Floor wiring harness 

→ Instrument 

panel wiring harness 

→ Front impact 

sensor (RH)

Correct or replace each wiring harness.

51

Floor wiring harness 

→ Passenger’s 

seat belt switch for COM terminal

Correct or replace the floor wiring 
harness.

52

Floor wiring harness 

→ Passenger’s 

seat belt switch for N/C terminal

Correct or replace the floor wiring 
harness.

57*, 58*

Floor wiring harness 

→ Side-airbag 

module (RH)

Correct or replace the floor wiring 
harness.

59, 60

Floor wiring harness 

→ Seat belt 

pre-tensioner (RH)

Correct or replace the floor wiring 
harness.

63*, 64*

Floor wiring harness 

→ Side impact 

sensor (RH)

Correct or replace the floor wiring 
harness.

65

Floor wiring harness 

→ Passenger’s 

seat belt switch for N/O terminal

Correct or replace the floor wiring 
harness.

66

Floor wiring harness 

→ Occupant 

classification sensor

Correct or replace the floor wiring 
harness.

SRS-ECU TERMINAL 
NO.

DESTINATION OF HARNESS

CORRECTIVE ACTION

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-29

WARNING

•

Inspection of the SRS-ECU connector harness 
should be carried out by the following procedure. 
Insert the backprobing tool into connector from 
harness side (rear side), and connect the tester to 
backprobing tool. If any tool other than backprob-
ing tool is used, it may cause damage to the har-
ness and other components. Furthermore, 
measurement should not be carried out by touch-
ing the backprobing tool directly against the termi-
nals from the front of the connector. The terminals 
are plated to increase their conductivity, so if they 
are touched directly by the backprobing tool, the 
plating may break, which will decrease reliability.

•

The SRS components and seat belt with pre-ten-
sioner should not be subjected to heat, so remove 
the SRS-ECU, driver’s and front passenger’s air 
bag modules, clock spring, side-airbag modules, 
and seat belt pre-tensioner before drying or baking 
the vehicle after painting.

•

SRS-ECU, air bag module, clock spring: 93

°

 C 

(200

°

 F) or more

•

Seat belt with pre-tensioner 90

°

C (194

°

 F) or 

more

•

After servicing the SRS system, check the warning 
light operation to make sure that the system func-
tions properly. (Refer to 

P.52B-3

).

•

Make certain that the ignition switch is in the 
"LOCK"(OFF) position when the scan tool is con-
nected or disconnected.

SRS AIR BAG DIAGNOSIS

INTRODUCTION TO DIAGNOSIS

M1524005000330

The SRS system is controlled by the SRS-ECU. The 
SRS-ECU judges how severe a collision is by detect-
ing signals from the left and right front impact sen-
sors and side impact sensors, front air bag analog 
G-sensor and front air bag safing G-sensor and 
side-airbag safing G-sensor. If the impact is over a 
predetermined level, the SRS-ECU sends an ignition 
signal. At this time, if the safing G-sensor is on, the 
SRS air bag will inflate. (The passenger's air bag 
may not inflate according to the occupant detection 
data from the occupant classification-ECU.) The 

SRS warning light in the combination meter alerts a 
malfunction of the SRS system. If the following 
symptoms occur even when the vehicle has not been 
in a collision, there may be a malfunction in the SRS 
system.

• The SRS warning light does not go off within 

approximately seven seconds after the ignition 
switch has been turned to the "ON" position.

• The SRS warning light does not illuminate when 

the ignition switch is turned to the "ON" position.

Refer to Post-collision Diagnosis when inspecting 
and servicing a vehicle that has been in a collision 
(Refer to 

P.52B-348

).

AC307379

AC301599

AC300928

SRS-HARNESS CONNECTOR

SRS-ECU HARNESS CONNECTOR
(REAR SIDE)

AB