Mitsubishi Evolution X. Manual - part 667

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-115

(5) Check for continuity between C-37 harness side connector 

terminals 1 and 2.
It should be an open circuit.

Q: Is it open circuit?

YES : Erase the diagnostic trouble code memory, and check 

the diagnostic trouble code. If DTC B1B13 sets, 
replace the SRS-ECU (Refer to 

P.52B-383

). Then go 

to Step 7.

NO :  Go to Step 6.

STEP 6. Check the harness for short circuit between 
SRS-ECU connector C-37 (terminal No.35 and 36) and knee 
air bag module connector C-39 (terminal No.2 and 1).
Q: Are harness wires between SRS-ECU connector C-37 

(terminal No.1 and 2) and knee air bag module 
connector C-39 (terminal No.2 and 1) in good condition?
YES : Go to Step 7.
NO :  Replace the harness wires between SRS-ECU 

connector C-37 and knee air bag module connector 
C-39. Then go to Step 7.

STEP 7. 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 B1C36 set?

YES : Return to Step 1. 
NO :  The procedure is complete.

AC608812FI

C-37 Harness side 
connector (front view)

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-116

DTC B1B18: Curtain Air Bag Module (LH) (Squib) System (Shorted to Squib Circuit Ground)

CURTAIN AIR BAG 
MODULE (SQUIB) (LH)

CONNECTOR
LOCK 
SWITCH

CONNECTOR
LOCK 
SWITCH

SRS-ECU

NOTE

: CONNECTOR COUPLED : ON

CONNECTOR UNCOUPLED : OFF

Curtain Air Bag Module (Squib) (LH) Circuit

CONNECTOR
LOCK SWITCH

AC708951AD

Connector: C-36

C-36 (Y)

AC708955AB

Connector: D-15

D-15 (Y)

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-117

CAUTION

If DTC B1B18 is set in the SRS-ECU, always diag-
nose the CAN main bus line.

.

CIRCUIT OPERATION

• The SRS-ECU judges how severe a collision is 

by detecting signals from the side impact sensors 
installed on the lower side of the center pillar. If 
the impact is over a predetermined level, the 
SRS-ECU sends an ignition signal. At this time, if 
the side collision safing G-sensor is on, the SRS 
air bag will inflate. 

• The ignition signal is input to the curtain air bag 

module (LH) to inflate the curtain air bag.

.

DTC SET CONDITIONS

This DTC is set if there is abnormal resistance 
between the input terminals of the curtain air bag 
module (LH) (squib).

.

TROUBLESHOOTING HITS

• Damaged wiring harnesses or connectors

• Short to the ground in the curtain air bag module 

(LH) (squib) harness

• Malfunction of the SRS-ECU

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: M.U.T.-III USB Cable

• MB991910: M.U.T.-III Main Harness A (Vehicles with 

CAN Communication System)

• MB991865: Dummy resistor

• MB991866: Resister harness

AC708970AB

Connector: F-28

F-28 (B)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-118

STEP 1. Using scan tool MB991958, diagnose the CAN bus 
line.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958. Refer to "How to connect the 

scan tool 

P.52B-28

."

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?

YES : Go to Step 2.
NO :  Repair the CAN bus line (Refer to GROUP 54C, 

Diagnosis 

P.54C-14

).

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

YES : Go to Step 3.
NO :  There is an intermittent malfunction such as poor 

engaged connector(s) or open circuit (Refer to 
GROUP 00, How to Use Troubleshooting/Inspection 
Service Points 

− How to Cope with Intermittent 

Malfunctions 

P.00-15

).

AC608435

Data link connector

MB991827

MB991824

MB991910

AB