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DTC B1407: Front impact sensor (RH) voltage error
 
 
cautionIf DTC 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 DTC to the SRS-ECU if a malfunction occurs.
 
 
DTC SET CONDITIONS
This DTC 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
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-IIISE), diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the scan tool ."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the CAN bus line found to be normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C, Diagnosis ).
 
STEP 2. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Check the DTC.
(1) Erase the diagnostic trouble code.
(2) Ignition: "LOCK" (OFF) position to "ON"
(3) On completion, check that the DTC is not set again.
Is the DTC 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 ground, and open circuit in FRH-, FRH+ line between SRS-ECU connector and front impact sensor (RH) connector.
noteAfter inspecting intermediate connector inspect the wiring harness. If the intermediate connector is damaged, repair or replace it.
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 DTC from memory, and check the diagnostic trouble code.
Is DTC B1417 set?
Replace the front impact sensor (RH) with a new one (Refer to ).
Go to Step 5.
 
STEP 5. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Is DTC B1407 set?
Replace the SRS-ECU (Refer to ).
An intermittent malfunction is suspected (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).