Mitsubishi Evolution X. Manual - part 691

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-211

STEP 5. Check the side-air bag module (RH) circuit. 
Measure the resistance at the SRS-ECU connector C-36.
(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 side-air bag module (RH) connector 
D-36 to short the squib circuit.

(3) Disconnect side-air bag module connector D-36.

CAUTION

Insert an insulator such as a cable tie to a depth of 4mm 
(0.16 inch) or more, otherwise the short spring will not be 
released.
(4) Insert a cable tie [3 mm (0.12 inch) wide, 0.5 mm (0.02 inch) 

thick] between terminals 33, 34 and the short spring to 
release the short spring.

(5) Measure at the wiring harness side.

(6) Check for continuity between C-36 harness side connector 

terminals 33 and 34.
It should be open circuit.

Q: Is it open circuit?

YES : Erase the diagnostic trouble code memory, and check 

the diagnostic trouble code. If DTC B1C2E sets, 
replace the SRS-ECU (Refer to 

P.52B-383

). Then go 

to Step 7.

NO :  Go to Step 6.

AC609027

A

AB

Lock lever

AC507303 CB

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)

GG

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-212

STEP 6. Check the harness wires for short circuit between 
SRS-ECU connector C-36 (terminal No.33 and 34) and 
side-air bag module (RH) connector D-36 (terminal No.1 
and 2).
Q: Are the harness wires between SRS-ECU connector 

C-36 (terminal No.33 and 34) and side-air bag module 
(RH) connector D-36 (terminal No.1 and 2) in good 
condition?
YES : Go to Step 7.
NO :  Repair the harness wires between SRS-ECU 

connector C-36 and side-air bag module (RH) 
connector D-36. 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 B1C2E set?

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

DTC B1C38: Driver's Pre-tensioner (Squib) System (Shorted to Squib Circuit Ground)

CONNECTOR
LOCK 
SWITCH

CONNECTOR
LOCK SWITCH

SEAT BELT
PRE-TENSIONER (LH)

SRS-ECU

Seat Belt Pre-Tensioner (LH) (Squib) Circuit

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-213

CAUTION

If DTC B1C38 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 front impact sensors and 
the front air bag analog 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. 

.

DTC SET CONDITIONS

This DTC is set if there is abnormal resistance 
between the input terminals of the driver's seat belt 
pre-tensioner (squib).

.

TROUBLESHOOTING HITS

• Damaged wiring harnesses or connectors

• Short to the ground in the driver's seat belt 

pre-tensioner (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

• MB991884: Resister harness

AC708951AD

Connector: C-36

C-36 (Y)

AC708955AF

Connector: D-25

D-25 (B)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-214

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 the "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 Cope with Intermittent 
Malfunction 

P.00-15

).

AC608435

Data link connector

MB991827

MB991824

MB991910

AB