Mitsubishi Lancer Evolution IX. Manual - part 630

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-33

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 driver’s seat belt 
pre-tensioner connector D-16 <LHD> or D-03 
<RHD> to short the squib circuit.

(2) Disconnect driver's seat belt pre-tensioner 

connector D-16 <LHD> or D-03 <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 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 29, 30 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 29 and 30.

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.29 
and 30) and driver’s seat belt pre-tensioner 
connector D-16 <LHD>, D-03 <RHD> 
(terminal No.2 and 1).

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

AN

Connector: D-16
<LHD>

Harness side 
connector 
(front view)

D-16 (B)

AC310471

Ai

Connector: D-03
<RHD>

Harness side 
connector 
(front view)

D-03 (B)

AC300147AW

Flat-tipped 
screwdriver

Locking button

D-16 <LHD>, 
D-03 <RHD> 
 Driver's seat 
belt pre-tensioner 
connector

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

AC200988 AM

A

A

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

Terminal

Section
A - A

Cable tie

Short spring

4 mm or more

AC006244

34 35 36 37 38 39 40 41 42

25 26 27 28 29 30 31 32 33

21 22

23 24

C-13 
Harness side connector 
(rear view)

AS

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-34

STEP 6. Check whether the diagnosis code is 
reset.

Q: Is diagnosis code 26 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.27: Driver's 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
(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

Driver's Seat Belt Pre-Tensioner (Squib) (LHD)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-35

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 driver's seat belt pre-ten-
sioner 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

• Improper connector contact

• Open circuit in the driver's seat belt pre-tensioner 

(squib) circuit

• Malfunction of the SRS-ECU

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

Driver's Seat Belt Pre-Tensioner (Squib) (RHD)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-36

DIAGNOSIS PROCEDURE

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

(2) Disconnect driver's seat belt pre-tensioner 

connector D-16 <LHD> or D-03 <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-16 

<LHD> or D-03 <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 27 set?

YES : 

Go to Step 2.

NO : 

Replace the driver's seat belt with 
pre-tensioner (Refer to 

P.52B-117

).

AC310465

AN

Connector: D-16
<LHD>

Harness side 
connector 
(front view)

D-16 (B)

AC310471

Ai

Connector: D-03
<RHD>

Harness side 
connector 
(front view)

D-03 (B)

AC300147AW

Flat-tipped 
screwdriver

Locking button

D-16 <LHD>, 
D-03 <RHD> 
 Driver's seat 
belt pre-tensioner 
connector

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

MB991884
MB991885

AC300975 AI

MB991865
(Dummy resistor : 3  )

MB991884
(Resistor
harness)

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