Mitsubishi Colt Ralliart. Manual — part 556

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-62

(3) Connect C-28 harness side connector to special

tool resistor harness (MB991884).

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 the following

terminals.

• SRS-ECU connector B-35 terminal No.7 and

special tool terminal No.1

• SRS-ECU connector B-35 terminal No.8 and

special tool terminal No.2

OK: Continuity (Less than 2

Ω)

Q: Are the check results normal?

YES : .

Go to Step 3.

NO : .

Repair the harness wires between

SRS-ECU connector B-35 (terminal No.7
and 8) and driver’s seat belt pre-tensioner
connector C-28 (terminal No.2 and 1).

STEP 3. Check whether the diagnosis code is
reset.

Q: Is diagnosis code No.27 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

).

AC201287BP

C-28

Harness side
connector

MB991884

13 14 15 16 17

19 20

5 6 7 8 9 10 11 12

1 2

3 4

18

2

1

AC208503 AD

B-35
Harness side
connectors (rear view)

Special tool
MB991884

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-63

Code No.28: Passenger's (front) seat belt pre-tensioner (squib) system (short-circuit between
terminals of the squib circuit)

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 one passenger’s (front)
seat belt pre-tensioner squib wire shorted to the
other. However, if no diagnosis code resets, the SRS
warning lamp will be switched off (diagnosis code will
be retained).

PROBABLE CAUSES

• Improper engaged connector or defective short

spring*

• Short circuit between the passenger's (front) seat

belt pre-tensioner (squib) circuit terminals

• Damaged connector(s)

• Malfunction of the SRS-ECU

NOTE: *: The squib circuit connectors integrate a
"short" spring (which prevents the air bag from
deploying unintentionally due to static electricity by
shorting the positive wire to the earth wire in the
squib circuit when the connectors are disconnected).
Therefore, if connector B-35 or C-20 is damaged or
improperly engaged, the short spring may not be
released when the connector is connected.

AC510233

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

SEAT BELT
PRETENSIONER
(LH)

SRS-ECU

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK SWITCH

NOTE

: CONNECTOR COUPLED: ON
CONNECTOR UNCOUPLED: OFF

Passenger's (Front) Seat Belt Pre-tensioner (Squib)

AB

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-64

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code.

Q: Is diagnosis code 34 set?

YES :

Go to Step 2.

NO :

Go to Step 3.

STEP 2. Connector lock check: SRS-ECU
connector B-35. (M.U.T.-III diagnosis code)
(1) Disconnect the negative battery terminal.

(2) Disconnect the connectors B-35 and then

reconnect them.

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

diagnosis code.

Q: Is diagnosis code 28 set?

YES :

Go to Step 4.

NO :

The procedure is complete. It is assumed
that diagnosis code 28 set as connector
B-35 or C-20 was engaged improperly.

STEP 3. Connector lock check: SRS-ECU
connector B-35 and passenger’s (front) seat belt
pre-tensioner connector C-20. (M.U.T.-III
diagnosis code)
(1) Disconnect the negative battery terminal.

(2) Disconnect connectors B-35 or C-20, and then

reconnect them. For connector C-20, use a
flat-tipped screwdriver to pull out the locking
button at the harness side connector, and then
disconnect the connector.

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

diagnosis code.

Q: Is diagnosis code 28 set?

YES :

Go to Step 4.

NO :

The procedure is complete. It is assumed
that diagnosis code 28 set as connector
B-35 or C-20 was engaged improperly.

AC206285

AF

B-35 (Y)

Connector: B-35

Harness side
connector
(rear view)

AC206285

AF

B-35 (Y)

Connector: B-35

Harness side
connector
(rear view)

AC207223 AE

Harness side
connector
(front view)

Connector: C-20

C-20 (B)

Centre

pillar

AC208430AE

Pre-tensioner

connector

Locking

button

Harness side

connector

Flat-tipped

screwdriver

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-65

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 passenger's (front) seat belt

pre-tensioner connector C-20. Use a flat-tipped
screwdriver to pull out the locking button at the
harness side connector, 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 C-20

harness side connector.

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

the diagnosis code.

Q: Is diagnosis code 28 set?

YES :

Go to Step 5.

NO :

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

P.52B-159

).

Then go to Step 6.

STEP 5. Resistance measurement at the
SRS-ECU connector B-35.
(1) Disconnect the negative battery terminal.

(2) Disconnect SRS-ECU connector B-35.

DANGER

To prevents the air bag from deploying unin-
tentionally, disconnect the passenger’s
(front) seat belt pre-tensioner connector C-20
to short the squib circuit.

(3) Disconnect passenger's (front) seat belt

pre-tensioner connector C-20. Use a flat-tipped
screwdriver to pull out the locking button at the
harness side connector, and then disconnect the
connector.

AC207223 AE

Harness side
connector
(front view)

Connector: C-20

C-20 (B)

Centre

pillar

AC208430AE

Pre-tensioner

connector

Locking

button

Harness side

connector

Flat-tipped

screwdriver

MB991865
(Dummy resistor : 3

Ω)

C-20 Harness side
connectors

MB991884
(Resistor
harness)

AG

AC206285

AF

B-35 (Y)

Connector: B-35

Harness side
connector
(rear view)

AC207223 AE

Harness side
connector
(front view)

Connector: C-20

C-20 (B)

Centre

pillar

AC208430AE

Pre-tensioner

connector

Locking

button

Harness side

connector

Flat-tipped

screwdriver

Main

Index

Group

TOC