Mitsubishi Galant (2004+). Manual — part 1586
SRS AIR BAG DIAGNOSIS
TSB Revision
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-237
DTC B1476: IG1 Power Supply Circuit System (Fuse No.22 Circuit) DTC B1477: IG1 Power Supply
Circuit System (Fuse No.23 Circuit)
IGNITION
SWITCH (IG1)
JUNCTION
BLOCK
SRS-ECU
IG1 Power Supply Circuit
SRS AIR BAG DIAGNOSIS
TSB Revision
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-238
CAUTION
If DTC B1476 <Fuse No.22> or B1477 <Fuse
No.23> is set in the combination meter, always
diagnose the CAN bus lines.
.
CIRCUIT OPERATION
• The SRS-ECU is powered from the ignition
switch (IG1).
• The SRS-ECU power is supplied from two cir-
cuits. Even if one circuit is shut off, the air bag
can inflate.
.
DTC SET CONDITIONS
This DTC is set if the voltage between the IG1 termi-
nals (fuse No.22 circuit or fuse No.23 circuit) and
ground is lower than a predetermined value for a
continuous period of five second or more. However, if
the vehicle condition returns to normal, DTC number
B1476 <Fuse No.22> or B1477 <Fuse No.23> will be
automatically erased, and the SRS warning light will
switch off.
.
TROUBLESHOOTING HINTS
• Damaged wiring harnesses or connectors
• Malfunction of the SRS-ECU
.
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)
• MB991223 (MB991222): Harness set (Probe)
AC305233 AO
CONNECTOR: C-22
C-22 (Y)
AC305362
CONNECTOR: C-121
C-121 (Y)
AD
SRS-ECU
AC305415
C-211
C-214
CONNECTORS: C-211, C-214
AR
SRS AIR BAG DIAGNOSIS
TSB Revision
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-239
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 "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 Cope with Intermittent
Malfunction
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-240
STEP 3. Check junction block fuse number 22 <B1476> or
23 <B1477>.
Q: Is the fuse burned out?
YES : Go to Step 6.
NO : Go to Step 4.
STEP 4. Check the power supply circuit for open circuit.
Measure the voltage at SRS-ECU connector C-121.
(1) Disconnect the negative battery terminal.
(2) Disconnect SRS-ECU connector C-121.
(3) Connect the negative battery terminal.
(4) Turn the ignition switch to the "ON" position.
CAUTION
Do not insert a test probe into the terminal from its front
side directly, as the connector contact pressure may be
weakened.
(5) Measure the voltage between C-121 harness side
connector terminal 23 <DTC B1476> or 24 <DTC B1477>
and body ground.
Voltage should measure 9 volts or more.
Q: Is the measured voltage within the specified range?
YES : Erase the diagnosis connector memory, and check
the diagnostic trouble code. If DTC B1476 or B1477
set, replace the SRS-ECU. (Refer to
).
Then go to Step 10.
NO : Go to Step 5.
AC308194
AB
FUSE No. 23
JUNCTION
BLOCK
FUSE No. 22
AC305362
CONNECTOR: C-121
C-121 (Y)
AH
SRS-ECU
C-121
HARNESS SIDE
CONNECTOR
(REAR VIEW)
42
31
38
27
21
41
28
39
22
30
25
47
36
33
44
34
45
37
48
26
29
23
40
32
43
35
46
24
B
A
AC308202
42
31
38
27
21
41
28
39
22
30
25
47
36
33
44
34
45
37
48
26
29
23
40
32
43
35
46
24
B
A
C-121 HARNESS SIDE
CONNECTOR (REAR VIEW)
AB
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст