Code No.B1407: Front Impact Sensor (RH) Power Supply Circuit
System
![](../../../img/52/W4X52E004A00ENG.png)
caution |
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 includes an analogue G sensor
and CPU, etc. The CPU monitors the analogue G sensor output signal. If the CPU
judges that the front air bags should be deployed, it sends a fire signal to
the SRS-ECU to deploy the front air bags. In addition, the CPU diagnoses the
internal components of the front impact sensor. If a malfunction occurs, it
requests the SRS-ECU to set a diagnosis code.
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 five seconds.
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 54F, 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 C-119 (terminal No.47 and 48) and front impact
sensor (RH) connector A-30 (terminal No.1 and 2).
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![](../../../img/52/AC313404AS00ENG.png)
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note |
After inspecting intermediate connector C-124
inspect the wiring harness. If the intermediate connector C-124 is
damaged, repair or replace it.
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Q.
Are the harness wires between SRS-ECU connector C-119 (terminal No.47 and
48) and front impact sensor (RH) (front) connector A-30 (terminal No.1 and
2) in good condition?
Go to Step 4.
Replace the harness wires between
SRS-ECU connector C-119 (terminal No.47 and 48) and front impact sensor
(RH) connector A-30 (terminal No.1 and 2).
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STEP 4. Check the front impact sensor (RH) (M.U.T.-III diagnosis
code).
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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 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 ). Then go to Step 5.
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STEP 5. Check whether the diagnosis code is reset.
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Q.
Is diagnosis code B1407 set?
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Replace the SRS-ECU (Refer to ).
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An
intermittent malfunction is suspected (Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points ).
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