Code No.B1407: Front impact sensor (RH) voltage error
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If diagnosis code B1407 is set in the SRS-ECU, always
diagnose the CAN main bus line.
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OPERATION
The front impact sensor transmits acceleration data to
the SRS-ECU. The SRS-ECU then determines whether to operate the front air
bags, and then outputs an ignition signal when necessary. The front impact
sensor also diagnoses itself, and sends a diagnosis code to the SRS-ECU if a
malfunction occurs.
DIAGNOSIS CODE SET CONDITIONS
This diagnosis code will set when
the power supply voltage to the front impact sensor (RH) remains less than a
predetermined value for one second.
PROBABLE CAUSES
- Damaged wiring harness or connectors
- Malfunction of the front impact sensor (RH)
- Malfunction of the SRS-ECU
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STEP 1. M.U.T.-III CAN bus diagnostics
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Use the 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 2.
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 Repair
the CAN bus line (Refer to GROUP 54D, Diagnosis  ).
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STEP 2. Check whether the diagnosis code is reset.
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Check again if the diagnosis code is
set.
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(1)Erase the diagnosis code.
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(2)Ignition: "LOCK" (OFF) position to "ON"
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(3)On completion, check that the diagnosis code is not
reset.
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Q.
Is the diagnosis code set?
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Go to Step 3.
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There
is an intermittent malfunction such as poor engaged connector(s) or open
circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
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STEP 3. Check the harness wires for open circuit or short circuit
between SRS-ECU connector D-24 (terminal No.47 and 48) and front impact
sensor (RH) connector A-37 (terminal No.1 and 2).
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| note |
After inspecting intermediate connector D-231
inspect the wiring harness. If the intermediate connector D-231 is
damaged, repair or replace it.
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Q.
Are the harness wires between SRS-ECU connector D-24 (terminal No.47 and
48) and front impact sensor (RH) (front) connector A-37 (terminal No.1 and
2) in good condition?
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Go to Step 4.
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Replace the harness wires between
SRS-ECU connector D-24 (terminal No.47 and 48) and front impact sensor (RH)
connector A-37 (terminal No.1 and 2).
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STEP 4. Check the front impact sensor (RH).
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(1)Disconnect the negative battery terminal.
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(2)Replace the front impact sensor (RH) with the front impact
sensor (LH).
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(3)Connect the negative battery terminal.
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(4)Erase diagnosis code from memory, and check the diagnosis
code.
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Q.
Is diagnosis code B1407 set?
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Replace the SRS-ECU (Refer to ).
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Replace the front impact sensor (RH)
with a new one (Refer to ).
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