Mitsubishi Evolution X. Manual — part 719

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-323

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 : Replace the slide adjuster (RH) (Refer to GROUP

52A, Front Seat Assembly

P.52A-24

).

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 B1BA7: Occupant Classification System Verification Required

CAUTION

If DTC B1BA7 is set in the occupant classifica-
tion-ECU, always diagnose the CAN main bus
lines.

.

CIRCUIT OPERATION

The load data from the weight sensor is classified
with the occupant classification-ECU, and its classi-
fied information is send to SRS-ECU by CAN bus
line. The SRS-ECU determines the air bag deploy-
ment based on this classified information, and con-
trols the power supply circuit to the inflator.

.

DTC SET CONDITIONS

This DTC is set if a light impact is detected by the
occupant classification-ECU.

.

TROUBLESHOOTING HINTS

• Malfunction of weight sensor

• Malfunction of occupant classification-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)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-324

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 B1BA7 set?

YES : Replace the slide adjuster (RH) (Refer to GROUP

52A, Front Seat Assembly

P.52A-24

).

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-325

DTC B1BA8: Occupant classification-ECU Out of Calibration not/Calibrated

CAUTION

If DTC B1BA8 is set in the occupant classifica-
tion-ECU, always diagnose the CAN main bus
lines.

.

CIRCUIT OPERATION

The load data from the weight sensor is classified
with the occupant classification-ECU, and its classi-
fied information is send to SRS-ECU by CAN bus
line. The SRS-ECU determines the air bag deploy-
ment based on this classified information, and con-
trols the power supply circuit to the inflator.

.

DTC SET CONDITION

This DTC is set when the 30 Kg (66 pounds) system
and 0 Kg (0 pound) system have not been executed.

.

TROUBLESHOOTING HINTS

• Zero calibration not executed

• 30 Kg (66 pounds) system and 0 Kg (0 pound)

system not executed

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

).

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-326

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 B1BA7 set?

YES : After executing zero calibration of the occupant

classification-ECU, execute 30 Kg (66 pounds)
system and 0 Kg (0 pound) system.

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 B1BBA: Passenger Seat Weight Sensor Power Supply Circuit

CAUTION

If DTC B1BBA is set in the occupant classifica-
tion-ECU, always diagnose the CAN main bus
lines.

.

CIRCUIT OPERATION

The load data from the weight sensor is classified
with the occupant classification-ECU, and its classi-
fied information is send to SRS-ECU by CAN bus
line. The SRS-ECU determines the air bag deploy-
ment based on this classified information, and con-
trols the power supply circuit to the inflator.

.

DTC SET CONDITIONS

This DTC is set if the weight sensor power supply
line is defective.

.

TROUBLESHOOTING HINTS

• The weight sensor may be defective.

• The occupant classification-ECU may be defec-

tive.

• 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)