Mitsubishi Evolution X. Manual — part 674

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-143

STEP 3. Check by dummy resistor connection.
(1) Disconnect the negative battery terminal.
(2) Disconnect the D-10 intermediate connector (connection

between curtain air bag harness and floor harness).

(3) Connect special tool MB991865 to special tool MB991866.

CAUTION

Do not insert a probe into the terminal from its front side
directly, as the connector contact pressure may be weak-
ened.
(4) Insert the probe of resistor harness, to which the dummy

resistor is installed, from the back of D-10 intermediate
connector (floor harness side).

(5) Connect the negative battery terminal.
(6) After erasing the diagnostic trouble code memory, check the

diagnostic trouble code again.

(7) Disconnect the negative battery terminal.
Q: Is DTC B1B20 set?

YES : Go to Step 4.
NO : Go to Step 5.

AC507310

D-10 Intermediate connector
(Curtain air bag harness side)

D-10
Intermediate
connector
(Floor harness side)

AI

MB991865
(Dummy resistor: 3 )

MB991866

(Resistor harness)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-144

STEP 4. Resistance measurement at the C-36 SRS-ECU
connector
(1) Disconnect the negative battery terminal.
(2) While pushing the part "A" indicated in the figure of the

harness side connector, turn the lock lever to the direction
of the arrow to release the lock lever, and disconnect the
C-36 SRS-ECU connector.

DANGER

To prevent the air bag from deploying unintentionally,
disconnect the intermediate connector D-10 to short
the squib circuit.

(3) Disconnect the D-10 intermediate connector (connection

between curtain air bag harness and floor harness).

CAUTION

The short spring may not be released due to the insuffi-
cient insertion. Therefore, insert the insulator for 4 mm (0.6
inch) or more.
(4) Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch)

thick] between terminal 39, 40 and the short spring to
release the short spring.

(5) Check for continuity between C-36 wiring harness side

connector terminal No. 39, 40 and body ground.
It should be open circuit.

Q: Is it open circuit?

YES : Go to Step 6.
NO : Repair the wiring harness.

AC609027

A

AB

Lock lever

AC507303 BZ

A

A

C-36 Harness side
connector (front view)

Section
A - A

Cable tie

Short spring

4 mm (0.16 inch) or more

Terminal

AC608812

C-36 Harness side
connector (front view)

FS

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-145

STEP 5. Resistance measurement at the D-10 intermediate
connector.
(1) Disconnect the negative battery terminal.

DANGER

To prevent the air bag from deploying unintentionally,
disconnect the curtain air bag module connector F-04
to short the squib circuit.

(2) Disconnect curtain air bag module (RH) F-04. Use a

flat-tipped screwdriver to unlock the locking button at the
harness side connector by withdrawing it toward you in two
stages, and then disconnect the connector.

(3) Disconnect the D-10 intermediate connector (connection

between curtain air bag harness and floor harness).

(4) Because the short spring is installed to the D-10

intermediate connector (curtain air bag harness side), insert
a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) thick]
between terminals 1, 2 and the short spring to release the
short spring.

CAUTION

Do not insert a probe into the terminal from its front side
directly as the connector contact pressure may be weak-
ened.
(5) Check for continuity between the D-10 intermediate

connector (module side) terminal No. 1, 2 and body ground.
It should be open circuit.

Q: Is it open circuit?

YES : Replace the curtain air bag module (squib) (Refer to

P.52B-409

).

NO : Repair the wiring harness.

STEP 6. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Erase the DTC.
(2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC B1B20 set?

YES : Replace SRS-ECU (Refer to

P.52B-383

).

NO : Intermittent Malfunction (Refer to GROUP 00, How to

Use Troubleshooting/Inspection Service Points

− How

to Cope with Intermittent Malfunction

P.00-15

).

AC609834AB

Locking
button

Flat-tipped
screwdriver

Inflator

Curtain air bag wiring
harness connector

AC700119

D-10 Intermediate
connector (module side )

22 mm or more

Cable tie

Short spring

AJ

AC608812GW

D-10 Intermediate connector
(Curtain air bag harness side)
(rear view)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-146

DTC B1B21: Curtain Air Bag Module (RH) (Squib) System (Shorted to Squib Circuit Power Supply)

SRS-ECU

NOTE

: CONNECTOR COUPLED : ON

CONNECTOR UNCOUPLED : OFF

Curtain Air Bag Module (Squib) (RH) Circuit

CURTAIN AIR BAG MODULE
(SQUIB) (RH)

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK
SWITCH

CONNECTOR
LOCK SWITCH

AC708951AD

Connector: C-36

C-36 (Y)

AC708955AC

Connector: D-10

D-10 (Y)