Mitsubishi Outlander GS45X. Manual — part 1440

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-255

STEP 4. Check the harness for open circuit between
SRS-ECU connector C-27 (terminal No.45 and 46) and the
driver's seat belt pre-tensioner D-121 (terminal No.1 and 2).
(1) Disconnect the negative battery terminal.
(2) While pushing the part "A" indicated in the figure of the

harness side connector, turn the lock lever to the direction
of the arrow to release the lock lever, and disconnect the
C-27 SRS-ECU connector.

DANGER

To prevent the seat belt pre-tensioner from deploying
unintentionally, disconnect the driver’s seat belt
pre-tensioner connector D-121 to short the squib cir-
cuit.

(3) Disconnect SRS-ECU connector C-27 and driver's seat belt

pre-tensioner connector D-121, and measure at the wiring
harness side. For connector D-121, use a flat-tipped
screwdriver to unlock the locking button at the harness side
connector by withdrawing it toward you in two stages, and
then disconnect the connector.

CAUTION

Insert an insulator such as a cable tie to a depth of 4mm
(0.16 inch) or more, otherwise the short spring will not be
released.

(4) Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch)

thick] between terminals 45, 46 and the short spring to
release the short spring.

AC507645

A

AC

Lock lever

AC507550AE

Seat belt
pre-tensioner

Harness side
connector

Locking
button

Flat-tipped
screwdriver

AC507303AN

A

A

C-27 Harness side
connector (front view)

Section
A - A

Cable tie

Short spring

4 mm or more

Terminal

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-256

(5) Connect D-121 harness side connector to special tool

MB991884.

(6) Check for continuity between the following terminals. It

should be less than 2 ohms.

• SRS-ECU connector C-27 (terminal No.45) and the spe-

cial tool (terminal No.2)

• SRS-ECU connector C-27 (terminal No.46) and the spe-

cial tool (terminal No.1)

Q: Does continuity exist?

YES : Erase the diagnostic trouble code memory, and

recheck if any DTC set. If DTC B1C3A set, replace
the SRS-ECU (Refer to

P.52B-436

). Then go to Step

5.

NO : Repair harness wires between SRS-ECU connector

C-27 and driver’s seat belt pre-tensioner connector
D-121. Then go to Step 5.

STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Erase the DTC.
(2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC B1C3A set?

YES : Return to Step 1.
NO : The procedure is complete.

AC201287

MB991884

FV

D-121 Harness side
connector (front view)

AC608812DF

2

1

Resistor harness
side connector

C-27 Harness side
connector (front view)

ZC501967

AC404789

AC701411AB

MB991824

MB991827

MB991910

Data link
connector

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-257

DTC B1C3B: Driver's Seat Belt Pre-tensioner (Squib) System (Short Circuit between Squib Circuit
Terminals)

CAUTION

If DTC B1C3B is set in the SRS-ECU, always diag-
nose the CAN main bus line.

.

CIRCUIT OPERATION

The SRS-ECU judges how severe a collision is by
detecting signals from the front impact sensors and
the front air bag analog G-sensor. If the impact is
over a predetermined level, the SRS-ECU sends an
ignition signal. At this time, if the front air bag safing
G-sensor is on, the pre-tensioner will deploy.

.

DTC SET CONDITIONS

This DTC is set if there is abnormal resistance
between the input terminals of the driver's side seat
belt pre-tensioner (squib).

.

TROUBLESHOOTING HITS

• Improper engaged connector or defective short

spring*

• Short circuit between the driver's seat belt

pre-tensioner (squib) circuit terminals

• Damaged connector(s)

• Malfunction of the SRS-ECU

: CONNECTOR COUPLED: ON
CONNECTOR UNCOUPLED: OFF

NOTE

Seat Belt Pre-Tensioner (Driver's side) (Squib) Circuit

SRS-ECU

SEAT BELT
PRE-TENSIONER
(LH)

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK
SWITCH

AC901076

C-27 (Y)

AC

Connector: C-27

AC901080AD

Connector: D-121

D-121 (B)

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-258

NOTE: *: The squib circuit connectors integrate a
"short" spring (which prevents the seat belt pre-ten-
sioner from deploying unintentionally due to static
electricity by shorting the positive wire to the ground
wire in the squib circuit when the connectors are dis-
connected) (Refer to

P.52B-3

). Therefore, if connec-

tor C-27 or D-121 is damaged or improperly
engaged, the short spring may not be released when
the connector is connected.

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: M.U.T.-III USB Cable

• MB991910: M.U.T.-III Main Harness A (Vehicles with

CAN Communication System)

• MB991865: Dummy resistor

• MB991884: Resister harness

STEP 1. Using scan tool MB991958, diagnose the CAN bus
line.

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958. Refer to "How to connect the

scan tool

P.52B-28

."

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?

YES : Go to Step 2 .
NO : Repair the CAN bus line (Refer to GROUP 54C,

Diagnosis

P.54C-17

).

ZC501967

AC404789

AC701411AB

MB991824

MB991827

MB991910

Data link
connector