Mitsubishi Colt Ralliart. Manual — part 545

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-18

Code No.3A: Curtain air bag module (squib) (RH) system (short-circuited between terminals of the
squib circuit)

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 one curtain air bag mod-
ule squib (RH) wire shorted to the other. However, if
no diagnosis code resets, the SRS warning lamp will
be switched off (diagnosis code will be retained).

PROBABLE CAUSES

• Improper engaged connector or defective short

spring*

• Short circuit between the curtain air bag module

(squib) (RH) circuit terminals

• Damaged connector(s)

• Malfunction of the SRS-ECU

NOTE: *: The squib circuit connectors integrate a
"short" spring (which prevents the air bag from
deploying unintentionally due to static electricity by
shorting the positive wire to the earth wire in the
squib circuit when the connectors are disconnected).
Therefore, if connector B-34,C-09 or C-07 is dam-
aged or improperly engaged, the short spring may
not be released when the connector is connected.

AC510221

CONNECTOR
LOCK
SWITCH

AIR BAG
DRIVE CIRCUIT

SRS-ECU

MICROC OMPUTER

CONNECTOR
LOCK
SWITCH

NOTE

CONNECTOR
COUPLED: ON
CONNECTOR
UNCOUPLED: OFF

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

CURTAIN AIR BAG
MODULE (SQUIB)
(RH)

Curtain Air Bag Module (Squib) (RH) Circuit

AB

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-19

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q: Is diagnosis code 34 set?

YES :

Go to Step 2.

NO :

Go to Step 3.

STEP 2. Connector lock check: SRS-ECU
connector B-34 (M.U.T.-III diagnosis code).
(1) Disconnect the negative battery terminal.

(2) Disconnect connectors B-34, and then reconnect

them.

(3) Connector the negative battery terminal.
(4) Erase the diagnosis code memory, and check the

diagnosis code.

Q: Is diagnosis code 3A set?

YES :

Go to Step 3.

NO :

The procedure is complete. It is assumed
that diagnosis code 3A set as connector
B-34 was engaged improperly.

STEP 3. Connector lock check: SRS-ECU
connector B-34, intermediate connector C-09 and
curtain air bag module connector C-07 (M.U.T.-III
diagnosis code).
(1) Disconnect the negative battery terminal.

(2) Disconnect connectors B-34, C-09 and C-07, and

then reconnect them. For connector C-07, use a
flat-tipped screwdriver to pull out the locking
button at the harness side connector, and then
disconnect the connector.

(3) Connector the negative battery terminal.

AC206285

AG

B-34 (Y)

Connector: B-34

Harness side
connector
(rear view)

343536373839404142

252627282930313233

2122

2324

AC206285

AG

B-34 (Y)

Connector: B-34

Harness side
connector
(rear view)

343536373839404142

252627282930313233

2122

2324

AC401577

Connector: C-07

C-07 (B)

Harness side
connector
(front view)

AB

AC208384 BJ

Locking button

C-07 Curtain air
bag module
connector

Flat-tipped
screwdriver

C-07 Harness side
connector

AC208385

Connector: C-09

C-09 (R)

Quarter panel

AD

Harness side

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-20

(4) Erase the diagnosis code memory, and check the

diagnosis code.

Q: Is diagnosis code 3A set?

YES :

Go to Step 4.

NO :

The procedure is complete. It is assumed
that diagnosis code 3A set as connector
B-34, C-09 or C-07 was engaged
improperly.

STEP 4. 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-09

(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 (MB991884) to the C-09

harness side connector by back probing.

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

the diagnosis code.

Q: Is diagnosis code 3A set?

YES :

Go to Step 5.

NO :

Go to Step 6.

STEP 5. Resistance measurement at the
SRS-ECU connector B-34.
(1) Disconnect the negative battery terminal.

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

DANGER

To prevents the air bag from deploying unin-
tentionally, disconnect the curtain air bag
harness connector C-09 to short the squib
circuit.

CAUTION

Insert an insulator such as a cable tie to a depth
of 4mm or more, otherwise the short spring will
not be released.
(3) Insert a cable tie [3 mm wide, 0.5 mm thick]

between terminals 29, 30 and the short spring to
release the short spring.

AC208385

Connector: C-09

C-09 (R)

Quarter panel

AD

Harness side

AC006042 CJ

MB991866
(Resistor harness)

C-09

Intermediate h

arness side

connector

C-09 Curtain air bag
module (RH) side connector

MB991865 (Dummy
resistor: 3

Ω)

AC206285

AG

B-34 (Y)

Connector: B-34

Harness side
connector
(rear view)

343536373839404142

252627282930313233

2122

2324

AC208385

Connector: C-09

C-09 (R)

Quarter panel

AD

Harness side

AC208765

Section
A - A

B-34
Harness side connector
(front view)

Cable tie

Short spring

4 mm or more

Terminal

AG

A

A

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-21

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 29 and 30.

OK: Open circuit

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

Repair the harness wire between SRS-ECU
connector B-34 (terminal No.29 and 30) and
harness side connector C-09 (terminal No.1
and 2).

STEP 6. Resistance measurement at intermediate
connector C-09.
(1) Disconnect the negative battery terminal.

DANGER

To prevents the air bag from deploying unin-
tentionally, disconnect the curtain air bag
module connector C-07 to short the squib
circuit.

(2) Disconnect curtain air bag module connector

C-07. Use a flat-tipped screwdriver to pull out the
locking button at the harness side connector, and
then disconnect the connector.

(3) Disconnect intermediate connector C-09

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

CAUTION

Insert an insulator such as a cable tie to a depth
of 4mm or more, otherwise the short spring will
not be released.
(4) Insert a cable tie [3 mm wide, 0.5 mm thick]

between terminals 1, 2 and the short spring to
release the short spring.

CAUTION

Do not insert a test probe into the terminal from
its front side directly as the connector contact
pressure may be weakened.

AC006244

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)

AW

AC401577

Connector: C-07

C-07 (B)

Harness side
connector
(front view)

AB

AC208384 BJ

Locking button

C-07 Curtain air
bag module
connector

Flat-tipped
screwdriver

C-07 Harness side
connector

AC303537

4 mm or more

C-09 Curtain air bag
module (RH) side
connector
(front view)

Terminal

Cable tie

A

Short
spring

Section
A - A

AJ

A

1 2

AC303538AG

C-09 Curtain air bag module (RH)
side connector (rear view)

Main

Index

Group

TOC