Mitsubishi Galant 9G. Manual — part 1450
SRS AIR BAG DIAGNOSIS
TSB Revision
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-210
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
."
(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,
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 DTCs set?
YES : Replace the SRS-ECU (Refer to
).
NO : There is an intermittent malfunction such as poor
engaged connector(s) or open circuit (Refer to
GROUP 00, How to Use Troubleshooting/Inspection
Service Points
− How to Cope with Intermittent
Malfunctions ).
AC305412
AB
MB991910
DATA LINK
CONNECTOR
MB991824
MB991827
AC305412
AB
MB991910
DATA LINK
CONNECTOR
MB991824
MB991827
SRS AIR BAG DIAGNOSIS
TSB Revision
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-211
DTC B1470: Seat Belt Pre-Tensioner (LH) (Squib) System Fault 1 (Short Circuit between Terminals of
the Squib Circuit)
CAUTION
If DTC B1470 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 driver's side seat
belt pre-tensioner (squib).
.
TROUBLESHOOTING HITS
• Improper engaged connector or defective short
spring*
• Short circuit between the driver's seat belt
pre-tensioner (squib) circuit terminals
• Damaged connector(s)
• Malfunction of the SRS-ECU
.
Driver's Seat Belt Pre-Tensioner (Squib) Circuit
SEAT BELT
PRE-TENSIONER
(LH)
PRE-TENSIONER(LH)
DRIVE CIRCUIT
SRS-ECU
CONNECTOR
LOCK SWITCH
CONNECTOR
LOCK SWITCH
: CONNECTOR CONNECTED: ON
CONNECTOR DICONNECTED: OFF
NOTE
AC305362
CONNECTOR: C-122
C-122 (Y)
AE
SRS-ECU
AC306920AB
CONNECTOR: D-21
D-21 (B)
FOWARD
CENTER
PILLAR
SRS AIR BAG DIAGNOSIS
TSB Revision
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-212
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-122 or D-21 is damaged or improperly
engaged, the short spring may not be released when
the connector is connected.
.
DIAGNOSIS
Required Special Tools:
• MB991958: Scan Tool (MUT-III Sub Assembly)
• MB991824: Vehicle Communication Interface (V.C.I.)
• MB991827: MUT-III USB Cable
• MB991910: MUT-III Main Harness A
• MB991865: Dummy resister
• MB991884: Resister harness (For Pre-tensioner)
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
."
(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,
AC305412
AB
MB991910
DATA LINK
CONNECTOR
MB991824
MB991827
SRS AIR BAG DIAGNOSIS
TSB Revision
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-213
STEP 2. 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 3.
NO : There is an intermittent malfunction such as poor
engaged connector(s) or open circuit (Refer to
GROUP 00, How to Use Troubleshooting/Inspection
Service Points
− How to Cope with Intermittent
Malfunctions ).
STEP 3. Using scan tool MB991958, read the diagnostic
trouble code.
(1) Turn the ignition switch to the "ON" position.
(2) Check if the DTC is set.
(3) Turn the ignition switch to the "LOOK (OFF)" position.
Q: Is DTC B1519 set?
YES : Go to Step 4.
NO : Go to Step 5.
AC305412
AB
MB991910
DATA LINK
CONNECTOR
MB991824
MB991827
AC305412
AB
MB991910
DATA LINK
CONNECTOR
MB991824
MB991827
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