Code No.B1407: Front impact sensor (RH) voltage error



caution If diagnosis code B1407 is set in the SRS-ECU, always diagnose the CAN main bus line.

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




DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III CAN bus diagnostics


Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?

Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).

STEP 2. Check whether the diagnosis code is reset.


Check again if the diagnosis code is set.
(1)Erase the diagnosis code.
(2)Ignition: "LOCK" (OFF) position to "ON"
(3)On completion, check that the diagnosis code is not reset.

Q. Is the diagnosis code set?

Go to Step 3.
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).

STEP 3. Check of short to power supply, short to earth, and open circuit in FRH-, FRH+ line between SRS-ECU connector and front impact sensor (RH) connector.


note After inspecting intermediate connector inspect the wiring harness. If the intermediate connector is damaged, repair or replace it.

Q. Is the check result normal?

Go to Step 4.
Repair the wiring harness.

STEP 4. Check the front impact sensor (RH).


(1)Disconnect the negative battery terminal.
(2)Alternate the front impact sensor (RH) and the front impact sensor (LH), and then install the alternated sensor.
(3)Connect the negative battery terminal.
(4)Erase diagnosis code from memory, and check the diagnosis code.

Q. Is diagnosis code B1417 set?

Replace the front impact sensor (RH) with a new one (Refer to ).
Go to Step 5.

STEP 5. Check whether the diagnosis code is reset.


Q. Is diagnosis code B1407 set?

Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).