B1418
DTC B1418: Front Impact Sensor (LH) Communication Error
DTC B1419: Front Impact Sensor (LH) Communication Impossible
CAUTION:
If diagnosis code B1418 or B1419 is set in the SRS-ECU, always diagnose the CAN main bus line.
CIRCUIT OPERATION
The front impact sensor includes an analog G sensor and CPU, etc. The CPU monitors the analog 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 diagnostic trouble code.
DTC SET CONDITIONS
These DTCs are set if communication between the front impact sensor (LH) and the SRS-ECU is not possible or faulty.
TROUBLESHOOTING HINTS
- Damaged wiring harnesses or connectors
- Malfunction of the front impact sensor (LH)
- Malfunction of the SRS-ECU
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
(1)
CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
Connect scan tool MB991958. Refer to "How to connect the scan tool Reading and Clearing Diagnostic Trouble Codes."
(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.
Q. Is the CAN bus line found to be normal?
YES Go to Step 2.
NO Repair the CAN bus line CAN Bus Diagnostics Chart).
STEP 2. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1)Erase the DTC.
(2)Turn the ignition switch to the "ON" position.
(3)Check if the DTC is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.
Q. Is the DTC set?
YES Go to Step 3.
NO There is an intermittent malfunction such as poor engaged connector(s) or open circuit How to Cope With Intermittent Malfunctions).
STEP 3. Check the front impact sensor (LH).
(1)Check that the negative battery terminal is disconnected. If the negative battery terminal is connected, disconnect it.
(2)Alternate the right front impact sensor and left front impact sensor, 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?
YES Replace the front impact sensor (LH) (Refer to Removal and Installation).
NO Go to Step 4
STEP 4. Wiring harness check between the A-45 front impact sensor
(LH) connector terminal No. 1/2 and the C-126 SRS-ECU connector terminal No. 17/27.
NOTE:
Prior to the wiring harness inspection, check the C-127 intermediate connector, and repair if necessary.
- Wiring harness check for open and short circuit between right front impact sensor and SRS-ECU
Q. Is the check result normal?
YES Go to Step 5
NO Repair the wiring harness.
STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1)Erase the DTC.
(2)Turn the ignition switch to the "ON" position.
(3)Check if the DTC is set.
(4)Turn the ignition switch to the "LOCK" (OFF) position.
Q. Is the diagnosis code No. B1418 or B1419 set?
YES Replace SRS-ECU (Refer to Service and Repair).
NO Intermittent malfunction How to Cope With Intermittent Malfunctions).