Mitsubishi Evolution X. Manual - part 703

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-259

STEP 9. Check the harness for open circuit between 
SRS-ECU connector C-36 (terminal No.61 and 62) and the 
ETACS-ECU connector C-313 (terminal No.4 and 2).
(1) Disconnect the negative battery terminal.
(2) Disconnect SRS-ECU connector C-36.
(3) 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.

(4) Disconnect the ETACS-ECU connector C-313.

(5) Check for continuity between the following terminals. It 

should be less than 2 ohms.

<Fuse No.12>

• SRS-ECU connector C-36 (terminal No.62) and the 

ETACS-ECU connector C-313 (terminal No.2)

<Fuse No.18>

• SRS-ECU connector C-36 (terminal No.61) and the 

ETACS-ECU connector C-313 (terminal No.4)

Q: Does continuity exist?

YES : Go to Step 10.
NO :  Replace the harness wire between SRS-ECU 

connector C-36 and the ETACS-ECU connector 
C-313.

STEP 10. 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 B210D set?

YES : Replace the SRS-ECU (Refer to 

P.52B-383

).

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

).

AC507645

A

AC

Lock lever

AC608812GP

C-313 Harness side 
connector (front view)

C-36 Harness side 
connector (front view)

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-260

DTC B212C: Open Circuit to IG1 Power Supply (Fuse No.12 Circuit)

 

DTC B212D: Open Circuit to IG1 Power Supply (Fuse No.18 Circuit)

ETACS-ECU

FUSIBLE
LINK

34

IGNITION
SWITCH (IG1)

IG1
RELAY

SRS-ECU

POWER 
SUPPLY

IG1 Power Supply Circuit

JOINT CONNECTOR (4)

JOINT CONNECTOR (5)

AC708951BY

C-37 (Y) C-36 (Y)

Connector:s C-36, C-37

AC708972AH

Connector: C-313

Junction block

C-313 (BR)

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-261

CAUTION

If DTC B212C (Fuse No.12) or B212D (Fuse No.18) 
is set in the SRS-ECU, always diagnose the CAN 
main bus lines.

.

CIRCUIT OPERATION

• The SRS-ECU is powered from the ignition 

switch (IG1).

• The SRS-ECU power is supplied from two cir-

cuits. Even if one circuit is shut off, the air bag 
can inflate.

.

DTC SET CONDITIONS

This code is set when an open circuit occurs in the 
power supply circuit to the SRS-ECU (terminal 
No.61) or in the power supply circuit to the SRS-ECU 
(terminal No.62).Also, if the code No. B212C and 
B212D are set at the same time, the battery voltage 
may have dropped. Therefore, check the battery first.

.

TROUBLESHOOTING HINTS

• Open circuit to power supply circuit

• Damaged wiring harnesses or connectors

• Malfunction of the SRS-ECU

• Malfunction of ETACS-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)

STEP 1. Power supply fuse check
Q: Is the fuse in good condition?

YES : Go to Step 3.
NO :  Go to Step 2.

STEP 2. Check for a blown fuse.
(1) Replace the fuse.
(2) Turn the ignition switch to the "ON" position, wait for at least 

one minute and then turn the switch off.

(3) Check the fuse.
Q: Is the fuse in good condition?

YES : Go to Step 3.
NO :   Repair the wiring harness between the fusible link 

(34) and the C-36 SRS-ECU connector terminal No. 
61/62, and replace the power supply fuse.

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-262

STEP 3. 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 4.
NO :  Repair the CAN bus line (Refer to GROUP 54C, 

Diagnosis 

P.54C-14

).

STEP 4. Using scan tool MB991958, diagnose the ETACS.

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) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?

YES : Diagnose the ETACS (Refer to GROUP 54A, ETACS, 

Diagnosis 

P.54A-582

).

NO :  Check the input signal of ETACS-ECU ignition switch 

(IG1) (Refer to GROUP 54A 

− ETACS, Symptom 

procedures 

P.54A-642

). Than go to step 5.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB