Code No. B1476
IG1 power supply open circuit (Fuse No. 15 circuit)
Code No. B1477 IG1
power supply
open circuit (Fuse No. 21 circuit)
caution |
If the diagnosis code B1476
(fuse No. 15) or B1477 (fuse No. 21) is set to SRS-ECU, be sure to diagnose
the CAN bus line.
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SRS-ECU has two independent battery power
supplies circuit (fuse Nos. 15 and 21) having
fuses.
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The code is set when the voltage between the
IG1 terminal (SRS-ECU terminal IG1A or No.
IG1B) and the earth drops below the specified value for 5 seconds
continuously. Also, if the
code No. B1476 and B1477 are set at the same time, the battery voltage may
have dropped. Therefore,
check the battery first.
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- Open circuit to power supply circuit
- Damaged wiring harness and connectors
- Malfunction of SRS-ECU
- Malfunction of ETACS-ECU
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STEP 1. Power supply fuse check.
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Q.
Is the fuse in good condition?
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Go to Step 3.
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Go to Step 2
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STEP 2. Fuse open circuit check
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(2)Turn the ignition switch to the "ON" position, wait for at
least one minute, and
then turn the switch OFF.
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Q.
Is the fuse in good condition?
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Go to Step 3.
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Repair
the wiring harness IG1A line between the junction block connector and the
SRS-ECU connector <fuse No. 15>, IG1B line between the junction
block connector and the
SRS-ECU connector <fuse No. 21> and replace the power supply
fuse.
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STEP 3. M.U.T.-III CAN bus diagnostics.
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Use M.U.T.-III to diagnose the CAN bus
lines.
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Q.
Is the check result normal?
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Go to Step 4.
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Repair the CAN bus lines (refer
to GROUP 54C - Troubleshooting ).
Then go to Step 4.
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STEP 4. M.U.T.-III other system diagnosis code.
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Check if the ETACS diagnosis code is
set.
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Q.
Is the diagnosis code set?
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Diagnose the ETACS (Refer to GROUP 54A
- ETACS - Troubleshooting ).
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Check the input signal of
ETACS-ECU ignition switch (IG1) (Refer to GROUP 54A - Check
Trouble by Using The Input Signal Check ). Then go to Step
5.
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STEP 5. Check whether the diagnosis code is reset.
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(1)Connect the negative battery terminal.
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(2)After erasing the diagnosis code memory, check the
diagnosis code again.
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(3)Disconnect the negative battery terminal.
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Q.
Is diagnosis code No. B1476 or B1477 set?
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Go to Step 6.
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Intermittent malfunction (Refer to
GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunction ).
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STEP 6. Resistance measurement at the SRS-ECU connector.
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![](../../../img/52/AC905015AC00ENG.png)
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(1)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 SRS-ECU
connectors. (2)Take the measurements below at the wiring harness side
connectors.
- Continuity GND1 line between wiring harness side connector
and body earth
OK: Continuity (less than 2 Ω)
Q.
Is the check result normal?
Go to Step 7.
Repair the wiring harness GND1 line
between the SRS-ECU connector and the body
earth.
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STEP 7. Voltage measurement at the SRS-ECU connector (IG1A, IG1B
line).
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(1)Check that the negative battery terminal is disconnected.
If the negative battery
terminal is connected, disconnect it.
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![](../../../img/52/AC905015AC00ENG.png)
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(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 SRS-ECU
connector. (3)Connect the negative battery terminal. (4)Ignition
switch: ON (5)Take the measurements below at the harness side connector.
- Voltage IG1A, IG1B line between SRS-ECU connector and
body earth
OK: 9 V or more (6)Disconnect the negative battery
terminal.
Q.
Is the check result normal?
Go to Step 9.
Go to Step
8.
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STEP 8. Resistance measurement at the SRS-ECU connector.
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(1)Check that the negative battery terminal is disconnected.
If the negative battery
terminal is connected, disconnect it.
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(2)Disconnect the junction block connector.
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![](../../../img/52/AC905015AC00ENG.png)
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(3)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 SRS-ECU
connector. (4)
- Continuity IG1A line between junction block connector and
SRS-ECU connector
- Continuity IG1B line between junction block connector and SRS-ECU
connector
OK: Continuity (less than 2 Ω)
Q.
Is the check result normal?
Replace the ETACS-ECU (Refer to GROUP
54A - ETACS-ECU ).
Repair the wiring harness IG1A line
between the junction block connector and the
SRS-ECU connector, IG1B line between the junction block connector and the
SRS-ECU connector.
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STEP 9. Check whether the diagnosis code is reset.
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Q.
Is diagnosis code No. B1476 or B1477 set?
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Replace SRS-ECU (Refer to ).
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Intermittent malfunction (Refer to
GROUP 00 - How to Use Troubleshooting/Inspection
Service Points - How to Cope with Intermittent Malfunction ).
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