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