Mitsubishi Evolution X. Manual - part 722

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-335

DTC B210D: Battery Voltage Low

 

DTC B210E: Battery Voltage High

Occupant Classification-ECU Power Supply Circuit

JOINT CONNECTOR (4)

JOINT CONNECTOR (3)

POWER 
SUPPLY

OCCUPANT 
CLASSIFICATION-ECU

FRONT SEAT ASSEMBLY (RH)

FUSIBLE
LINK

34

ETACS-ECU

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

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CAUTION

If DTC B210D, B210E is set in the occupant clas-
sification-ECU, always diagnose the CAN main 
bus lines.

.

TROUBLE JUDGMENT

The occupant classification-ECU sets DTC B210D if 
the power supply fuse voltage decreases to the 
specified value or less, and sets DTC B210E if the 
power supply fuse voltage increases to the specified 
value or more. However, when the status returns to 
normal, the occupant classification-ECU automati-
cally erases DTCs B210D and B210E.

.

TECHNICAL DESCRIPTION (COMMENT)

The power supply fuse or the occupant classifica-
tion-ECU may have a problem.

.

TROUBLESHOOTING HINTS

• The power supply fuse may be defective.

• The occupant classification-ECU may be defec-

tive.

• The battery may be defective.

• The generator may be defective.

• The wiring harness or connectors may have 

loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector

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. Wiring harness check between the fusible link (34) 
and the D-39-2 occupant classification-ECU connector 
terminal No. 21.

•  Short circuit check for SRS-ECU power supply wire

Q: Is the check result normal?

YES : Replace the power supply fuse.
NO :  Repair the wiring harness. And than replace the 

power supply fuse.

AC708954 AN

Connector: D-39-2

D-39-2

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

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STEP 3. Battery check.
Refer to GROUP 54A, Battery Test 

P.54A-9

.

Q: Is the check result normal?

YES : Go to Step 4.
NO :  Charge or replace the battery.

STEP 4. Measure the voltage at the ETACS-ECU connector.
(1) Disconnect the C-309 ETACS-ECU connector.
(2) Measure the voltage between the C-309 harness side 

connector terminal No. 1 and the body ground.

• The voltage should measure 12 volts (battery positive 

voltage).

Q: Is the measured voltage approximately 12 volts (battery 

positive voltage)?
YES : Go to Step 6.
NO :  Go to Step 5.

STEP 5. Wiring harness check between the fusible link (34) 
and the C-309 ETACS-ECU connector terminal No. 1.

•  Open circuit check for ETACS-ECU power supply wire

Q: Is the check result normal?

YES : Go to Step 10.
NO :  Repair the wiring harness.

STEP 6. 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) Erase the DTC.
(3) Turn the ignition switch to the "ON" position.
(4) Check if the DTC is set.
(5) 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 7.

AC709344

C-309 Harness side 
connector (rear view)

AE

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

SRS AIR BAG DIAGNOSIS

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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

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STEP 7. 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 8.
NO :  Repair the CAN bus line (Refer to GROUP 54C, 

Diagnosis 

P.54C-14

).

STEP 8. 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 9.
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