Mitsubishi Lancer Evolution IX. Manual - part 632

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-41

(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 
C-13, D-03 <LHD> or D-16 <RHD> was 
engaged improperly.

STEP 4. Check the diagnosis code by connecting 
a dummy resistor. (M.U.T.-II/III diagnosis code)
(1) Disconnect the negative battery terminal.

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

pre-tensioner connector D-03 <LHD> or D-16 
<RHD>. 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 D-03 

<LHD> or D-16 <RHD> 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-117

).

AC310465

AO

Connector: D-03
<LHD>

Harness side 
connector 
(front view)

D-03 (B)

AC310471

AJ

Connector: D-16
<RHD>

Harness side 
connector 
(front view)

D-16 (B)

AC300147AX

Flat-tipped 
screwdriver

Locking button

D-03 <LHD>, 
D-16 <RHD> 
Passenger's (front) 
seat belt 
pre-tensioner 
connector

D-03 <LHD>, D-16 <RHD> 
Harness side connector

MB991884
MB991885

AC103283AY

D-03 <LHD>, D-16 <RHD> 
Harness side connector

MB991884
(Resistor
Harness)

MB991865 
(Dummy Resistor : 3  )

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-42

STEP 5. Resistance measurement at the 
SRS-ECU connector C-13

(1) Disconnect SRS-ECU connector C-13.

DANGER

To prevents the air bag from deploying unin-
tentionally, disconnect the passenger’s 
(front) seat belt pre-tensioner connector D-03 
<LHD> or D-16 <RHD> to short the squib cir-
cuit.

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

pre-tensioner connector D-03 <LHD> or D-16 
<RHD>. Use a flat-tipped screwdriver to pull out 
the locking button at the harness side connector, 
and then disconnect the connector.

CAUTION

Insert an insulator such as a cable tie to a depth 
of 4 mm or more, otherwise the short spring will 
not be released.
(3) Insert a cable tie [3 mm wide, 0.5 mm thick] 

between terminals 27, 28 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) Resistance measurement between C-13 harness 

side connector terminals 27 and 28.

OK: Open circuit.

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Repair the harness wires between 
SRS-ECU connector C-13 (terminal No.7 
and 8) and passenger’s (front) seat belt 
pre-tensioner connector D-03 <LHD> or 
D-16 <RHD> (terminal No.1 and 2).

AC101951

Connector: C-13

SRS-ECU

AL

C-13 (Y)

21

252627 282930 313233
34 35 3637 38394041 42

22

23 24

Harness side 
connector 
(rear view)
 

AC310465

AO

Connector: D-03
<LHD>

Harness side 
connector 
(front view)

D-03 (B)

AC310471

AJ

Connector: D-16
<RHD>

Harness side 
connector 
(front view)

D-16 (B)

AC300147AX

Flat-tipped 
screwdriver

Locking button

D-03 <LHD>, 
D-16 <RHD> 
Passenger's (front) 
seat belt 
pre-tensioner 
connector

D-03 <LHD>, D-16 <RHD> 
Harness side connector

AC100393

AB

AQ

A

A

D-03 <LHD>, D-16 <RHD> 
Harness side connector
(front view)

Terminal

Section
A - A

Cable tie

Short spring

4 mm or more

AC100326

34 35 36 37 38 39 40 41 42

25 26 27 28 29 30 31 32 33

21 22

23 24

AQ

C-13 Harness side 
connector 
(rear view)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-43

STEP 6. Check whether the diagnosis code is 
reset. 

Q: Is diagnosis code 28 set?

YES : 

Replace the SRS-ECU (Refer to 

P.52B-109

).

NO : 

An intermittent malfunction is suspected 
(Refer to GROUP 00 

− How to Use 

Troubleshooting/Inspection Service Points 

P.00-5

). 

Code No.29: Passenger's (front) seat belt pre-tensioner (squib) system (open-circuited in the squib 
circuit)

CONNECTOR
LOCK
SWITCH

CONNECTOR
LOCK
SWITCH

AIR BAG DRIVE CIRCUIT

MICROCOMPUTER

SRS-ECU

SEAT BELT
PRE-TENSIONER
(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 : Gray     R : Red     P : Pink     V : Violet

NOTE

: CONNECTOR
  COUPLED: ON
  CONNECTOR
  UNCOUPLED: OFF

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

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-44

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 outputs an 
ignition signal. At this time, if the front air bag safing 
G-sensor is on, the seat belt pre-tensioner will 
deploy. 

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if the passenger's (front) 
seat belt pre-tensioner squib 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

• Open circuit in the passenger's (front) seat belt 

pre-tensioner (squib) circuit

• Improper connector contact

• Malfunction of the SRS-ECU

CONNECTOR
LOCK
SWITCH

CONNECTOR
LOCK
SWITCH

AIR BAG DRIVE CIRCUIT

MICROCOMPUTER

SRS-ECU

SEAT BELT
PRE-TENSIONER
(LH)

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

NOTE

: CONNECTOR
  COUPLED: ON
  CONNECTOR
  UNCOUPLED: OFF

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