Mitsubishi Colt Ralliart. Manual - part 567

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-106

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

diagnosis code.

Q: Is diagnosis code 71 out put?

YES : 

Go to Step 4.

NO : 

The procedure is complete. It is assumed 
that diagnosis code 71 set as connector 
B-34 was engaged improperly.

STEP 3. Connector lock check: SRS-ECU 
connector B-34 and side-airbag module (RH) 
connector C-25 (M.U.T.-III diagnosis code)
(1) Disconnect the negative battery terminal.

(2) Disconnect connectors B-34 and C-25 and then 

reconnect them.

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

diagnosis code.

Q: Is diagnosis code 71 out put?

YES : 

Go to Step 4.

NO : 

The procedure is complete. It is assumed 
that diagnosis code 71 set as connector 
B-34 or C-25 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 the side-airbag module (RH) 

connector C-25.

(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) Insert special tool (MB991866) into the C-25 

harness side connector by backprobing.

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

diagnosis code. 

Q: Is diagnosis code 71 set?

YES : 

Go to Step 5.

NO : 

Replace the frame assembly of the front 
seat (RH) (Refer to GROUP 52A, Front Seat 

P.52A-23

). 

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

AC401575

Connector: C-25

AB

C-25 (R)

2 1

Harness side
connector
(front view)

AC401575

Connector: C-25

AB

C-25 (R)

2 1

Harness side
connector
(front view)

AC006042 CL

MB991866
(Resistor harness)

C-25 Harness side
connector

C-25 Side-airbag
module (RH) connector

MB991865 (Dummy
resistor: 3

 

Ω)

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-107

STEP 5. Resistance measurement at the 
SRS-ECU connector B-34

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

DANGER

To prevents the air bag from deploying unin-
tentionally, disconnect the side-airbag mod-
ule (RH) connector C-25 to short the squib 
circuit.

(2) Disconnect side-airbag module connector C-25.

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 23, 24 and the short spring to 
release the short spring.

(4) Measure at the wiring harness side.

CAUTION

Do not insert a test probe into the terminal from 
its front side directly as the connector contact 
pressure may be weakened.
(5) Resistance measurement between B-34 harness 

side connector terminals 23 and 24.

OK: Open circuit

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the harness wires between 
SRS-ECU connector B-34 (terminal No.23 
and 24) and side-airbag module (RH) 
connector C-25 (terminal No.1 and 2).

STEP 6. Check whether the diagnosis code is 
reset.

Q: Is diagnosis code 71 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

).

AC206285

AG

B-34 (Y)

Connector: B-34

Harness side 
connector 
(rear view)

343536373839404142

252627282930313233

2122

2324

AC401575

Connector: C-25

AB

C-25 (R)

2 1

Harness side
connector
(front view)

AC100396

Section
A - A

B-34 Harness side connector
(front view)

Cable tie

Short spring

4 mm or more

Terminal

A

AW

A

34 35 36 37 38 39 40 41 42

25 26 27 28 29 30 31 32 33

21 22

23 24

AC100764

B-34 Harness side connector
(rear view)

AR

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-108

Code No.72: Side-airbag module (squib) (RH) system (open-circuited in the squib circuit)

OPERATION

• The SRS-ECU judges how severe a collision is 

by detecting signals from the left and right side 
impact sensors. If the impact is over a predeter-
mined level, the SRS-ECU sends an ignition sig-
nal. At this time, if the side-airbag safing 
G-sensor is on, the SRS side-airbag will inflate.

• The ignition signal is input to the side-airbag 

module to inflate the side-airbag.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if the side-airbag squib 
(RH) wire(s) are open-circuited. However, if no diag-
nosis code resets, the SRS warning lamp will be 
switched off (diagnosis code will be retained). 

PROBABLE CAUSES

• Open circuit in the side-airbag module (RH) 

(squib) circuit

• Improper connector contact

• Malfunction of the SRS-ECU

AC510242

NOTE

CONNECTOR
COUPLED: ON
CONNECTOR
UNCOUPLED: OFF

CONNECTOR
LOCK
SWITCH

AIR BAG DRIVE 
CIRCUIT

MICRO COMPUTER

SRS-ECU

SIDE-AIRBAG 
MODULE 
(SQUIB) 
(RH)

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

Side-airbag Module (RH) (Squib) Circuit

AB

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-109

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 the side-airbag module (RH) 

connector C-25.

(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) Insert special tool (MB991866) into the C-25 

harness side connector by backprobing.

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

diagnosis code. 

Q: Is diagnosis code 72 set?

YES : 

Go to Step 2.

NO : 

Replace the frame assembly of the front 
seat (RH) (Refer to GROUP 52A, Front Seat 

P.52A-23

). 

STEP 2. Resistance measurement between 
SRS-ECU connector B-34 (terminal No.23 and 24) 
and the side-airbag module (RH) connector C-25 
(terminal No.1 and 2)

(1) Disconnect SRS-ECU connector B-34 and 

side-airbag module (RH) connector C-25.

CAUTION

Do not insert a test probe into the terminal from 
its front side directly as the connector contact 
pressure may be weakened.
(2) Resistance measurement between the following 

terminals. 

• SRS-ECU connector B-34 terminal No.23 and 

the side-airbag module (RH) connector C-25 
terminal No.2

• SRS-ECU connector B-34 terminal No.24 and 

the side-airbag module (RH) connector C-25 
terminal No.1

OK: Continuity (Less than 2 

Ω)

AC401575

Connector: C-25

AB

C-25 (R)

2 1

Harness side
connector
(front view)

AC006042 CL

MB991866
(Resistor harness)

C-25 Harness side
connector

C-25 Side-airbag
module (RH) connector

MB991865 (Dummy
resistor: 3

 

Ω)

AC206285

AG

B-34 (Y)

Connector: B-34

Harness side 
connector 
(rear view)

343536373839404142

252627282930313233

2122

2324

AC401575

Connector: C-25

AB

C-25 (R)

2 1

Harness side
connector
(front view)

34 35 36 37 38 39 40 41 42

25 26 27 28 29 30 31 32 33

21 22

23 24

1 2

AC100382

B-34 
Harness side 
connectors
(rear view)

C-25 Harness side connector
(rear view)

AR

Main

Index

Group

TOC