Code No.B1408: Front impact sensor (RH) communication error
Code No.B1409: Front impact sensor (RH) communication impossible


caution If diagnosis code No. B1408 or B1409 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


The diagnosis code is set if the communication between the right front impact sensor and SRS-ECU is abnormal (No. B1408), or impossible (No. B1409).

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.
Use 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 - Troubleshooting ).

STEP 2. Check whether the diagnosis code is reset.
(1)Connect the negative battery terminal.
(2)After erasing the diagnosis code memory, check the diagnosis code again.
(3)Disconnect the negative battery terminal.

Q. Is the diagnosis code No. B1408 or B1409 set?
Go to Step 3
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).

STEP 3. Check the front impact sensor (RH) .
(1)Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
(2)Alternate the front impact sensor (RH) and front impact sensor (LH), and then install the alternated sensors.
(3)Connect the negative battery terminal.
(4)After erasing the diagnosis code memory, check the diagnosis code again.
(5)Disconnect the negative battery terminal.

Q. Is the diagnosis code No. B1408 or B1409 set?
Replace the front impact sensor (RH) (Refer to ).
Go to Step 4

STEP 4.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 5
Repair the wiring harness.

STEP 5. Check whether the diagnosis code is reset.

Q. Is the diagnosis code No. B1408 or B1409 set?
Replace SRS-ECU (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction ).