Mitsubishi Grandis. Manual - part 1011

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-96

STEP 6. Check the curtain air bag module (RH). 
(MUT-III diagnosis code)
(1) Disconnect the negative battery terminal.

(2) Disconnect curtain air bag module (RH) 

connector G-04. 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 G-04 

harness side connector.

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

the diagnosis code.

Q: Is diagnosis code B1440 set?

YES : 

Go to Step 7.

NO : 

Replace the curtain air bag module (RH) 
(Refer to 

P.52B-231

). 

STEP 7. Check the curtain air bag module (RH) 
circuit. Resistance measurement at the SRS-ECU 
connector C-118

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

DANGER

To prevents the air bag from deploying 
unintentionally, disconnect the curtain air 
bag module (RH) connector G-04 to short the 
squib circuit.

(2) Disconnect curtain air bag module (RH) 

connector G-04. Use a flat-tipped screwdriver to 
unlock the locking button at the harness side 
connector by withdrawing it toward you in two 

AC302575AD

 G-04 (B)

Connector: G-04

Harness side
(front view)

Roof centre duct

AC208384AM

G-04
Curtain air bag
module connector 

Flat-tip screw
driver

Locking button

G-04
Harness side
connector

AC301553AI

MB991865
(Dummy resistor : 3 

ΩΩ

MB991884
(Resistor
harness)

G-04 Harness side connector

AC311438 AC

C-118 (Y)

Connector: C-118

Harness side
(front view)

AC302575AD

 G-04 (B)

Connector: G-04

Harness side
(front view)

Roof centre duct

AC208384AM

G-04
Curtain air bag
module connector 

Flat-tip screw
driver

Locking button

G-04
Harness side
connector

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-97

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 bar will not 
be released.
(3) Insert a cable tie [3 mm wide, 0.5 mm thick] 

between terminals 61, 62 and the short bar 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) Resistance measurement between C-118 

harness side connector terminals 61 and 62.

OK: Open circuit

Q: Is the check result normal?

YES : 

Go to Step 8.

NO : 

Repair the harness wire between SRS-ECU 
connector C-118 (terminal No.61and 62) 
and curtain air bag module (RH) connector 
G-04 (terminal No.1 and 2).

STEP 8. Check whether the diagnosis code is 
reset.

Q: Is diagnosis code B1440 set?

YES : 

Replace the SRS-ECU. (Refer 

to

P.52B-223

). 

NO : 

The procedure is complete. If no 
malfunctions are found in all steps, an 
intermittent malfunction is suspected (Refer 
to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

P.00-5

). 

AC301609

Section
A - A

C-118
Harness side connector
(front view)

Cable tie

Short spring

4 mm or more

Terminal

A

A

AC

AC301571

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)

AC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-98

Code No.B1441: Curtain air bag module (squib) (RH) system (open-circuited in the squib circuit)

CAUTION

If diagnosis code B1441 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 side impact sensors and 
the side air bag safing G-sensor. If the impact is over 
a predetermined level, the SRS-ECU outputs an 
ignition signal. At this time, if the side air bag safing 
G-sensor is on, the curtain air bag module will 
deploy. 

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if curtain air bag module 
squib (RH) wire(s) are open-circuited. However, if no 
diagnosis code resets, the SRS warning lamp will be 
switched off (diagnosis code will be retained).

PROBABLE CAUSES

• Improper connector contact

• Open circuit in the curtain air bag module (squib) 

(RH) circuit

• 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

SRS-ECU

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK SWITCH

: CONNECTOR
  CONNECTED: ON
  CONNECTOR
  DISCONNECTED: OFF

NOTE

CURTAIN AIR BAG
MODULE
(SQUIB) (RH)

Curtain Air Bag Module (Squib) (RH) Circuit

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-99

STEP 3. Check the curtain air bag module (RH). 
(MUT-III diagnosis code.)
(1) Disconnect the negative battery terminal.

(2) Disconnect curtain air bag module (RH) 

connector G-04. 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 G-04 

harness side connector.

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

the diagnosis code.

Q: Is diagnosis code B1441 set?

YES : 

Go to Step 4.

NO : 

Replace the curtain air bag module (RH) 
(Refer to 

P.52B-231

). 

STEP 4. Resistance measurement between 
SRS-ECU connector C-118 (terminal No.61 and 
62) and the curtain air bag module (RH) 
connector G-04 (terminal No.1 and 2)

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

curtain air bag module (RH) connector G-04, and 
measure at the wiring harness side. For 
connector G-04, use a flat-tipped screwdriver to 
unlock the locking button at the harness side 
connector by withdrawing it toward you in two 

AC302575AD

 G-04 (B)

Connector: G-04

Harness side
(front view)

Roof centre duct

AC208384AM

G-04
Curtain air bag
module connector 

Flat-tip screw
driver

Locking button

G-04
Harness side
connector

AC301553AI

MB991865
(Dummy resistor : 3 

ΩΩ

MB991884
(Resistor
harness)

G-04 Harness side connector

AC311438 AC

C-118 (Y)

Connector: C-118

Harness side
(front view)

AC302575AD

 G-04 (B)

Connector: G-04

Harness side
(front view)

Roof centre duct

AC208384AM

G-04
Curtain air bag
module connector 

Flat-tip screw
driver

Locking button

G-04
Harness side
connector