Mitsubishi Colt Ralliart. Manual - part 550

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-38

(3) Connect special tool dummy resistor (MB991865) 

to special tool resistor harness (MB991866).

CAUTION

Do not insert a test probe into the terminal from 
its front side directly as the connector contact 
pressure may be weakened.
(4) Connect special tool (MB991866) to the C-13 

harness side connector by backprobing.

(5) Connect the negative battery terminal.
(6) Erase diagnosis code memory, and check the 

diagnosis code.

Q: Is diagnosis code 4E set?

YES : 

Go to Step 2.

NO : 

Go to Step 3.

STEP 2. Voltage measurement at the SRS-ECU 
connector B-34.
(1) Disconnect the negative battery terminal.

(2) Disconnect SRS-ECU connector B-34.
(3) Connect the negative battery terminal.

(4) Turn the ignition switch to the "ON" position.

CAUTION

Do not insert a test probe into the terminal from 
its front side directly as the connector contact 
pressure may be weakened.
(5) Voltage measurement between B-34 harness 

side connector terminals 27, 28 and body earth.

OK: 0 V

Q: Is the check results normal?

YES : 

Go to Step 4.

NO : 

Repair the harness wire between SRS-ECU 
connector B-34 (terminal No.27 and 28) and 
curtain air bag module (LH) side connector 
C-13 (terminal No.2 and 1).

STEP 3. Voltage measurement at the curtain air 
bag harness connector C-13.
(1) Disconnect the negative battery terminal.

(2) Disconnect intermediate connector C-13 

(connection between curtain air bag harness and 
floor harness).

(3) Connect the negative battery terminal.
(4) Turn the ignition switch to the "ON" position.

AC006042 CK

MB991866
(Resistor harness)

C-13 

Intermediate h

arness side

connector

MB991865 (Dummy
resistor: 3

 

Ω)

C-13 Curtain air bag
module (LH) side connector

AC206285

AG

B-34 (Y)

Connector: B-34

Harness side 
connector 
(rear view)

343536373839404142

252627282930313233

2122

2324

AC100341

34 35 36 37 38 39 40 41 42

25 26 27 28 29 30 31 32 33

21 22

23 24

B-34 Harness side 
connector (rear view)

AU

AC209027

Connector: C-13 

C-13 (R)

Quarter panel

AC

Harness side

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-39

CAUTION

Do not insert a test probe into the terminal from 
its front side directly as the connector contact 
pressure may be weakened.
(5) Voltage measurement between C-13 curtain air 

bag module (LH) side connector terminals 1, 2 
and body earth.

OK: 0 V

Q: Is the check results normal?

YES : 

Replace the curtain air bag module (Refer 

to 

P.52B-152

).

NO : 

Repair the harness wire between curtain air 
bag module (LH) connector C-13 (terminal 
No.1 and 2) and curtain air bag module 
connector C-10 (terminal No.1and 2).

STEP 4. Check whether the diagnosis code is 
reset.

Q: Is diagnosis code 4E set?

YES : 

Replace the SRS-ECU (Refer to 

P.52B-143

).

NO : 

An intermittent malfunction is suspected 
(Refer to GROUP 00, How to Cope with 
Intermittent Malfunction 

P.00-13

).

Code No.4F: Curtain air bag module (squib) (LH) system (short-circuited to the earth)

AC303709

2

1

AG

C-13 
Curtain air bag module (LH) 
side connector (rear view)

AC510222

CURTAIN AIR BAG
MODULE (SQUIB)
(LH)

AIR BAG
DRIVE CIRCUIT

SRS-ECU

MICRO COMPUTER

Wire colour code
B : Black     LG : Light green     G : Green     L : Blue     W : White     Y : Yellow     SB : Sky blue
BR : Brown     O : Orange     GR : Grey     R : Red     P : Pink     V : Violet   

CONNECTOR
LOCK
SWITCH

CONNECTOR
LOCK
SWITCH

NOTE

CONNECTOR
COUPLED: ON
CONNECTOR
UNCOUPLED: OFF

Curtain Air Bag Module (Squib) (LH) Circuit

AB

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-40

OPERATION

The SRS-ECU judges how severe a collision is by 
detecting signals from the side impact sensors and 
the side-airbag safing G-sensor. If the impact is over 
a predetermined level, the SRS-ECU sends an igni-
tion signal. At this time, if the side-airbag safing 
G-sensor is on, the curtain air bag module will 
deploy. 

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if the curtain air bag mod-
ule squib (LH) wire(s) are short-circuited to the earth.

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Short to the earth in the curtain air bag module 

(squib) (LH) harness

• Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check the diagnosis code by connecting 
a dummy resistor (M.U.T.-III diagnosis code).
(1) Disconnect the negative battery terminal.

(2) Disconnect intermediate connector C-13 

(connection between curtain air bag wiring 
harness and instrument panel wiring harness).

(3) Connect special tool dummy resistor (MB991865) 

to special tool resistor harness (MB991866).

CAUTION

Do not insert a test probe into the terminal from 
its front side directly as the connector contact 
pressure may be weakened.
(4) Connect special tool (MB991866) to the C-13 

harness side connector by backprobing.

(5) Connect the negative battery terminal.
(6) Erase diagnosis code memory, and check the 

diagnosis code.

Q: Is diagnosis code 4F set?

YES : 

Go to Step 2.

NO : 

Go to Step 3.

STEP 2. Resistance measurement at the 
SRS-ECU connector B-34.
(1) Disconnect the negative battery terminal.

(2) Disconnect SRS-ECU connector B-34.

(3) Disconnect intermediate connector C-13 

(connection between curtain air bag wiring 
harness and instrument panel wiring harness). 

AC209027

Connector: C-13 

C-13 (R)

Quarter panel

AC

Harness side

AC006042 CK

MB991866
(Resistor harness)

C-13 

Intermediate h

arness side

connector

MB991865 (Dummy
resistor: 3

 

Ω)

C-13 Curtain air bag
module (LH) side connector

AC206285

AG

B-34 (Y)

Connector: B-34

Harness side 
connector 
(rear view)

343536373839404142

252627282930313233

2122

2324

AC209027

Connector: C-13 

C-13 (R)

Quarter panel

AC

Harness side

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-41

CAUTION

Do not insert a test probe into the terminal from 
its front side directly as the connector contact 
pressure may be weakened.
(4) Resistance measurement between B-34 harness 

side connector terminals 27, 28 and body earth.

OK: Open circuit

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the harness wire between SRS-ECU 
connector B-34 (terminal No.27 and 28) and 
harness side connector C-13 (terminal No.2 
and 1).

STEP 3. Resistance measurement at the curtain 
air bag harness connector C-13.
(1) Disconnect the negative battery terminal.

(2) Disconnect intermediate connector C-13 

(connection between curtain air bag wiring 
harness and instrument panel wiring harness).

(3) Disconnect curtain air bag harness connector 

C-10. Use a flat-tipped screwdriver to pull out the 
locking button at the harness side connector, and 
then disconnect the connector.

CAUTION

Do not insert a test probe into the terminal from 
its front side directly as the connector contact 
pressure may be weakened.
(4) Resistance measurement between C-13 curtain 

air bag module (LH) side connector terminals 1, 2 
and body earth.

OK: Open circuit

Q: Is the check result normal?

YES : 

Replace the curtain air bag module (Refer 

to 

P.52B-152

).

NO : 

Repair the harness wire between curtain air 
bag module (LH) connector C-13 (terminal 
No.1 and 2) and curtain air bag module 
connector C-10 (terminal No.1 and 2).

AC100343

343536373839404142

252627282930313233

2122

2324

B-34 Harness side connector 
(rear view)

AL

AC209027

Connector: C-13 

C-13 (R)

Quarter panel

AC

Harness side

AC401577

Connector: C-10

C-10 (B)

Harness side
connector
(front view)

AC

AC208384BK

C-10
Curtain air bag
module connector 

Flat-tipped 
screwdriver

Locking button

C-10
Harness side
connector

AC303710

2

1

AF

C-13 Curtain air bag module 
side connector (rear view)

Main

Index

Group

TOC