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 front impact sensor (RH) and SRS-ECU is abnormal (No. B1408), or impossible (No. B1409).
PROBABLE CAUSES
- Damaged wiring harnesses or connectors
- Malfunction of the front impact sensor(RH)
- Malfunction of the SRS-ECU
|
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 set again.
|
|
(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 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.
|
|
(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 diagnosis code No. B1408 or B1409 set?
|
|
Go to Step 4.
|
|
|
|
Replace the front impact sensor (RH) (Refer to ).
|
|
|
|
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 connector(RH).
|
|
Q.
Is the check result normal?
|
|
Go to Step 5.
|
|
|
|
Repair the wiring harness.
|
|
|
|
STEP 5. Check whether the diagnosis code is set again.
|
|
Q.
Is 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 ).
|
|
|