Mitsubishi Colt Ralliart. Manual — part 568

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-110

Q: Are the check results normal?

YES :

Go to Step 3.

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 3. Check whether the diagnosis code is
reset.

Q: Is diagnosis code 72 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.75: Side-airbag module (squib) (RH) system (short-circuited to the power supply)

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 short-circuited to the power supply.

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Short to the power supply in the side-airbag mod-

ule (RH) (squib) harness

• 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-111

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 75 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. Voltage 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 (RH) connector

C-25.

(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 23 and 24 and body
earth.

OK: 0 V

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

AC208819

B-34 Harness side connector
(rear view)

AE

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-112

Q: Is the check result normal?

YES :

Go to Step 3.

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 3. Check whether the diagnosis code is
reset.

Q: Is diagnosis code 75 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.76: Side-airbag module (squib) (RH) system (short-circuited to the earth)

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 short-circuited to the earth.

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Short to earth in the side-airbag module (RH)

(squib) harness

• 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-113

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 76 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 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 (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.
(3) Resistance measurement between B-34 harness

side connector terminals 23, 24 and body earth.

OK: Open circuit

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

AC100384

B-34 Harness side connector
(rear view)

AR

Main

Index

Group

TOC