Mitsubishi Galant 9G. Manual — part 1432
SRS AIR BAG DIAGNOSIS
TSB Revision
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-138
DTC B1423: Side-Airbag Module (RH) (Squib) System Fault Ground Circuit (Short-Circuited to
Ground)
CAUTION
If DTC B1423 is set in the combination meter,
always diagnose the CAN bus lines.
.
CIRCUIT OPERATION
• The SRS-ECU judges how severe a collision is
by detecting signals from the left and right side
impact sensors. If the impact is over a predeter-
mined level, the SRS-ECU sends an ignition sig-
nal. At this time, if the side-airbag safing
G-sensor is on, the SRS side-airbag will inflate.
• The ignition signal is input to the side-airbag
module to inflate the side-airbag.
.
DTC SET CONDITIONS
This DTC is set if there is abnormal resistance
between the input terminals of the side-airbag mod-
ule (RH) (squib).
.
TROUBLESHOOTING HINTS
• Damaged wiring harnesses or connectors
• Short to ground in the side-airbag module (RH)
(squib) harness
• Malfunction of the SRS-ECU
.
SIDE AIR BAG
MODULE
(SQUIB) (RH)
AIR BAG DRIVE CIRCUIT
SRS-ECU
CONNECTOR
LOCK SWITCH
CONNECTOR
LOCK SWITCH
Side-Airbag Module (RH) (Squib) Circuit
NOTE
: CONNECTOR
CONNECTED
: ON
CONNECTOR
DISCONNECTED
: OFF
AC305362
CONNECTOR: C-120
C-120 (Y)
AC
SRS-ECU
AC307779
D-32 (R)
AC
CONNECTOR : D-32
SRS AIR BAG DIAGNOSIS
TSB Revision
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-139
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 (Vehicles with CAN
communication system)
• MB991865: Dummy resistor
• MB991866: 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
scan tool
."
(2) Turn the ignition switch to "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?
YES : Go to Step 2
NO : Repair the CAN bus lines (Refer to GROUP 54C,
Diagnosis-Can Bus Diagnostic Chart ).
AC305412
AB
MB991910
DATA LINK
CONNECTOR
MB991824
MB991827
SRS AIR BAG DIAGNOSIS
TSB Revision
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-140
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. Check the side-airbag module (RH). (Using scan
tool MB991958, read the diagnostic trouble code.)
(1) Disconnect the negative battery terminal.
(2) Disconnect the side-airbag module (RH) connector D-32.
(3) Connect special tool MB991865 to special tool MB991866.
CAUTION
Do not insert a test probe into the terminal from its front
side directly, as the connector contact pressure may be
weakened.
(4) Insert special tool MB991866 into the D-32 harness side
connector by backprobing.
(5) Connect the negative battery terminal.
(6) Erase the diagnostic trouble code memory, and check the
diagnostic trouble code.
Q: Is DTC B1423 set?
YES : Go to Step 4.
NO : Replace the seatback frame of the front seat (RH)
(Refer to GROUP 52A, Front Seat
go to Step 6.
AC305412
AB
MB991910
DATA LINK
CONNECTOR
MB991824
MB991827
AC307779
D-32 (R)
AD
2
1
HARNESS SIDE
CONNECTOR
(REAR VIEW)
CONNECTOR : D-32
AC006042BO
MB991866
(RESISTOR HARNESS)
D-32 HARNESS SIDE
CONNECTOR
D-32 SIDE-AIRBAG
MODULE (RH) CONNECTOR
MB991865 (DUMMY
RESISTOR: 3
Ω
)
SRS AIR BAG DIAGNOSIS
TSB Revision
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-141
STEP 4. Check the side-airbag module (RH) circuit.
Measure the resistance at the SRS-ECU connector C-120.
(1) Disconnect SRS-ECU connector C-120.
DANGER
To prevent the air bag from deploying unintentionally,
disconnect the side-airbag module (RH) connector
D-32 to short the squib circuit.
(2) Disconnect side-airbag module (RH) connector D-32.
CAUTION
Do not insert a test probe into the terminal from its front
side directly, as the connector contact pressure may be
weakened.
(3) Check for continuity between C-120 harness side connector
terminals 57, 58 and body ground.
It should be open circuit.
Q: Does continuity exist?
YES : Go to Step 5.
NO : Erase the diagnostic trouble code memory, and check
the diagnostic trouble code. If DTC B1423 sets,
replace the SRS-ECU (Refer to
). Then go
to Step 6.
AC305362
CONNECTOR: C-120
C-120 (Y)
AG
SRS-ECU
63
55
51
69
61
66
58
65
64
56 57
68
60
67
59
70
62
53
52 B
A
54
C-120
Harness side
connector
(rear view)
AC307779
D-32 (R)
AD
2
1
HARNESS SIDE
CONNECTOR
(REAR VIEW)
CONNECTOR : D-32
AC301576
63
55
51
69
61
66
58
65
64
56 57
68
60
67
59
70
62
53
52 B
A
54
C-120 HARNESS SIDE
CONNECTOR
(REAR VIEW)
AC
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