Mitsubishi Evolution X. Manual - part 647

 

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Mitsubishi Evolution X. Manual - part 647

 

 

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-35

DIAGNOSTIC TROUBLE CODE PROCEDURES <SRS-ECU>

DTC B1206: Passenger’s Air Bag OFF Indicator Light (Open Circuit)

CAUTION

If DTC B1206 is set in the SRS-ECU, always diag-
nose the CAN main bus line.

.

CIRCUIT OPERATION

• Power for the passenger’s air bag OFF indicator 

light is supplied from the ignition switch (IG1).

• The passenger’s air bag OFF indicator light illu-

minates when the ignition switch is turned to the 
"ON" position and goes out after approximately 
seven seconds if there is not a malfunction in the 
SRS system.

.

INTERFACE
CIRCUIT

SRS-ECU

AIR BAG OFF 
INDICATOR 
LIGHT 
PASSENGER'S 
SIDE

ETACS-ECU

Air Bag OFF Indicator Light Drive Circuit

INSTRUMENT CENTER PANEL

AC708951AB

C-37 (Y)

C-124

Connectors: C-37, C-124

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-36

DTC SET CONDITIONS

This DTC will be set if an open circuit has occurred in 
the wiring harness between the passenger’s air bag 
OFF indicator light and the SRS-ECU.

.

TROUBLESHOOTING HINTS

• Damaged wiring harnesses or connectors

• Malfunction of the SRS-ECU

• Malfunction of the passenger’s air bag OFF indi-

cator light

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. 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

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-37

STEP 3. Check the passenger’s air bag OFF indicator light.
(1) It is checked whether the passenger’s air bag OFF indicator 

light is normal (Refer to 

P.52B-30

).

Q: Is the check result normal?

YES : Go to Step 4.
NO :  Replace instrument center panel (Refer to GROUP 

52A 

− Instrument Panel Assembly 

P.52A-2

).

STEP 4. Check the harness for open circuit between 
SRS-ECU connector C-37 (terminal No.18) and the 
instrument center panel connector C-124 (terminal No.11).
(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-37 SRS-ECU connector.

(3) Disconnect the instrument center panel connector C-124.

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

should be less than 2 ohms.

• SRS-ECU connector C-37 (terminal No.18) and the 

instrument center panel connector C-124 (terminal 
No.11)

Q: Does continuity exist?

YES : Go to Step 5.
NO :  Repair the harness wires. Then go to Step 5.

STEP 5. Measure the voltage at the instrument center 
panel connector.
(1) Disconnect the negative battery terminal.
(2) Disconnect the C-124 instrument center panel connector.
(3) Connect the negative battery terminal.
(4) Ignition switch: ON.
(5) Measure the voltage between the C-124 harness side 

connector terminal No. 8 and body ground.

• The voltage should measure approximately 12 volts 

(battery positive voltage).

Q: Is the measured voltage approximately 12 volts (battery 

positive voltage)?
YES : Go to Step 6.
NO :  Repair the wiring harness between the fusible link 

(34) and the C-124 instrument center panel connector 
terminal No. 8.

AC506734

A

AD

Lock lever

AC608812

C-37 Harness side 
connector (front view)

C-124 Harness side 
connector (front view)

EV

AC608813

C-124 Harness side 
connector (front view)

AY

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-38

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 B1206 set?

YES : Replace 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

).

DTC B1207: Passenger’s Air Bag OFF Indicator Light (Short Circuit between Circuit Terminal)

INTERFACE
CIRCUIT

SRS-ECU

AIR BAG OFF 
INDICATOR 
LIGHT 
PASSENGER'S 
SIDE

ETACS-ECU

Air Bag OFF Indicator Light Drive Circuit

INSTRUMENT CENTER PANEL

 

 

 

 

 

 

 

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