Mitsubishi Evolution X. Manual — part 700
SRS AIR BAG DIAGNOSIS
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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-247
STEP 4. Check the harness for open circuit between
SRS-ECU connector C-36 (terminal No.43 and 44) and the
passenger's seat belt pre-tensioner connector D-40
(terminal No.2 and 1).
(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 seat belt pre-tensioner from deploying
unintentionally, disconnect the passenger’s seat belt
pre-tensioner connector D-40 to short the squib cir-
cuit.
(3) Disconnect SRS-ECU connector C-36 and passenger's
seat belt pre-tensioner connector D-40. For connector D-40,
use a flat-tipped screwdriver to unlock the locking button at
the harness side connector by withdrawing it toward you in
two stages, and then disconnect the connector.
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 43, 44 and the short spring to
release the short spring.
AC507645
A
AC
Lock lever
AC609576AB
Pre-tensioner
Harness side
connector
Locking
button
Flat-tipped
screwdriver
AC507303 CD
A
A
C-36 Harness side
connector (front view)
Section
A - A
Cable tie
Short spring
4 mm (0.16 inch) or more
Terminal
SRS AIR BAG DIAGNOSIS
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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-248
(5) Connect D-40 harness side connector to special tool
MB991884.
(6) Check for continuity between the following terminals. It
should be less than 2 ohms.
• SRS-ECU connector C-36 (terminal No.43) and the spe-
cial tool (terminal No.1)
• SRS-ECU connector C-36 (terminal No.44) and the spe-
cial tool (terminal No.2)
Q: Does continuity exist?
YES : Erase the diagnostic trouble code memory, and check
the diagnostic trouble code. If DTC B1C49 sets,
replace the SRS-ECU (Refer to
). Then go
to Step 5.
NO : Replace the harness wires between SRS-ECU
connector C-36 passenger’s seat belt pre-tensioner
connector D-40. Then go to Step 5.
STEP 5. 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 B1C49 set?
YES : Return to Step 1.
NO : The procedure is complete.
AC201287EM
D-40 Harness side
connector
MB991884
(Resistor harness)
AC608812GO
C-36 Harness side
connector (front view)
Resistor harness
side connector
SRS AIR BAG DIAGNOSIS
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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-249
DTC B1C4A: Front Passenger's Pre-tensioner (Squib) System (Short Circuit between Squib Circuit
Terminals)
CAUTION
If DTC B1C4A 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 passenger’s seat
belt pre-tensioner (squib).
.
TROUBLESHOOTING HITS
• Improper engaged connector or defective short
spring*
• Short circuit between the passenger's seat belt
pre-tensioner (squib) circuit terminals
• Damaged connector(s)
• Malfunction of the SRS-ECU
SEAT BELT
PRE-TENSIONER (RH)
CONNECTOR
LOCK
SWITCH
CONNECTOR
LOCK SWITCH
SRS-ECU
Seat Belt Pre-Tensioner (RH) (Squib) Circuit
AC708951AD
Connector: C-36
C-36 (Y)
AC708954 AH
Connector: D-40
D-40 (B)
SRS AIR BAG DIAGNOSIS
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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-250
NOTE: *: The squib circuit connectors integrate a
"short" spring (which prevents the seat belt pre-ten-
sioner from deploying unintentionally due to static
electricity by shorting the positive wire to the ground
wire in the squib circuit when the connectors are dis-
connected) (Refer to
). Therefore, if connec-
tor C-36 or D-40 is damaged or improperly engaged,
the short spring may not be released when the con-
nector is connected.
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
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
."
(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,
).
AC608435
Data link connector
MB991827
MB991824
MB991910
AB
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