Mitsubishi Grandis. Manual — part 1020

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-132

STEP 6. Check the seat belt pre-tensioner (RH).
(MUT-III diagnosis code.)
(1) Disconnect the negative battery terminal.

(2) Disconnect seat belt pre-tensioner (RH)

connector D-32. 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.

(3) Connect special tool dummy resistor (MB991865)

to special tool resistor harness (MB991884).

(4) Connect special tool MB991884 to the D-32

harness side connector.

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

the diagnosis code.

Q: Is diagnosis code B1460 set?

YES :

Go to Step 7.

NO :

Replace the seat belt pre-tensioner (RH)
(Refer to

P.52B-239

). Then go to Step 8.

STEP 7. Check the passenger's seat belt
pre-tensioner circuit. Resistance measurement at
the SRS-ECU connector C-118.

(1) Disconnect SRS-ECU connector C-118.

DANGER

To prevent the seat belt pre-tensioner from
deploying unintentionally, disconnect the
seat belt pre-tensioner (RH) connector D-32
to short the squib circuit.

(2) Disconnect seat belt pre-tensioner (RH)

connector D-32. Use a flat-tipped screwdriver to
unlock the locking button at the harness side
connector by withdrawing it toward you in two

AC302394AC

D-32 (B)

Connector: D-32

Centre
pillar

Front vehicle

Harness side
(front view)

AC103556AX

Locking button

Flat-tip screw
driver

D-32 Harness
side connector

D-32 Seat belt
pre-tensioner (RH)
connector

MB991884
MB991885

AC103283AU

MB991865
(Dummy resistor : 3

Ω)

MB991884
(Resistor
harness)

D-32 Harness side
connector

AC311438 AC

C-118 (Y)

Connector: C-118

Harness side
(front view)

AC302394AC

D-32 (B)

Connector: D-32

Centre
pillar

Front vehicle

Harness side
(front view)

AC103556AX

Locking button

Flat-tip screw
driver

D-32 Harness
side connector

D-32 Seat belt
pre-tensioner (RH)
connector

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-133

stages, and then disconnect the connector.

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 59, 60 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.
(4) Check for continuity between C-118 harness side

connector terminals 59 and 60.

OK: Open circuit.

Q: Is the check result normal?

YES :

Go to Step 8.

NO :

Repair the harness wires between
SRS-ECU connector C-118 (terminal No.59
and 60) and seat belt pre-tensioner (RH)
connector D-32 (terminal No.1 and 2).

STEP 8. Check whether the diagnosis code is
reset.

Q: Is diagnosis code B1460 set?

YES :

Replace the SRS-ECU (Refer

to

P.52B-223

).

NO :

An intermittent malfunction is suspected
(Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

P.00-5

).

AC301608

Section
A - A

C-118 Harness side
connector (front view)

Cable tie

Short spring

4 mm or more

Terminal

A

AG

A

AC301572

63

55

51

69

61

66

58

65

64

56 57

68

60

67

59

70

62

53

52 B

A

54

C-118 Harness side
connector (rear view)

AG

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-134

Code No.B1461: Seat Belt Pre-Tensioner (RH) (Squib) System Fault 2 (Open in the Squib Circuit)

CAUTION

If diagnosis code B1461 is set in the SRS-ECU,
always diagnose the CAN main bus line.

OPERATION

The SRS-ECU judges how severe a collision is by
detecting signals from the front impact sensors and
the front air bag analogue 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.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if there is abnormal
resistance between the input terminals of the seat
belt pre-tensioner (RH) (squib).

PROBABLE CAUSES

• Open circuit in the seat belt pre-tensioner (RH)

(squib) circuit

• Improper connector contact

• Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. MUT-III CAN bus diagnostics

Use the MUT-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the CAN bus line (Refer to GROUP
54D, Diagnosis

P.54D-16

).

STEP 2. Check whether the diagnosis code is
reset.

Check again if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition: LOCK (OFF) position to ON
(3) On completion, check that the diagnosis code is

not reset.

Q: Is the diagnosis code set?

YES :

Go to Step 3.

NO :

There is an intermittent malfunction such as
poor engaged connector(s) or open circuit
(Refer to GROUP 00, How to Cope with
Intermittent Malfunction

P.00-5

).

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

SEAT BELT
PRETENSIONER
(RH)

SRS-ECU

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK SWITCH

: CONNECTOR
CONNECTED: ON
CONNECTOR
DISCONNECTED: OFF

NOTE

Seat Belt Pre-Tensioner (RH) (Squib) Circuit

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-135

STEP 3. Check the seat belt pre-tensioner (RH).
(MUT-III diagnosis code.)
(1) Disconnect the negative battery terminal.

(2) Disconnect seat belt pre-tensioner connector

(RH) D-32. 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.

(3) Connect special tool dummy resistor (MB991865)

to special tool resistor harness (MB991884).

(4) Connect special tool MB991884 to the D-32

harness side connector.

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

the diagnosis code.

Q: Is diagnosis code B1461 set?

YES :

Go to Step 4.

NO :

Replace the passenger's seat belt
pre-tensioner (Refer to

P.52B-239

).

STEP 4. Resistance measurement between
SRS-ECU connector C-118 (terminal No.59 and
60) and the seat belt pre-tensioner (RH)
connector D-32 (terminal No.1 and 2).

(1) Disconnect SRS-ECU connector C-118 and seat

belt pre-tensioner (RH) connector D-32. For
connector D-32, 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.

(2) Connect D-32 harness side connector to special

AC302394AC

D-32 (B)

Connector: D-32

Centre
pillar

Front vehicle

Harness side
(front view)

AC103556AX

Locking button

Flat-tip screw
driver

D-32 Harness
side connector

D-32 Seat belt
pre-tensioner (RH)
connector

MB991884
MB991885

AC103283AU

MB991865
(Dummy resistor : 3

Ω)

MB991884
(Resistor
harness)

D-32 Harness side
connector

AC311438 AC

C-118 (Y)

Connector: C-118

Harness side
(front view)

AC302394AC

D-32 (B)

Connector: D-32

Centre
pillar

Front vehicle

Harness side
(front view)

AC103556AX

Locking button

Flat-tip screw
driver

D-32 Harness
side connector

D-32 Seat belt
pre-tensioner (RH)
connector

AC201287BG

D-32
Harness side
connector

MB991884