DTC B1408: Front Impact Sensor (RH) Communication Error; DTC B1409: Front Impact Sensor (RH) Communication Impossible: Diagnosis

WARNING: This page is about a different car, the 2014 Mitsubishi Outlander. However, it is still accessible from the selected car via links, so may be relevant.

STEP 1. Using scan tool (M.U.T.-III), diagnose the CAN bus line.
CAUTION: To prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
1. Connect scan tool (M.U.T.-III). 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.
Q: Is the CAN bus line found to be normal?
1. YES: Go to Step 2.
2. NO: Repair the CAN bus line (Refer to DIAGNOSIS ). Then go to Step 2.
STEP 2. Recheck for diagnostic trouble code.
Check again if the DTC is stored.
1. Erase the DTC.
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is stored.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC stored?
1. YES: Go to Step 3.
2. NO: There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to 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 the front impact sensor (LH), and then install the alternated sensor.
3. Connect the negative battery terminal.
4. After erasing the DTC memory, check the DTC again.
5. Disconnect the negative battery terminal.
Q: Is DTC B1408 or B1409 stored?
1. YES: Replace the front impact sensor (RH) with a new one. (Refer to SIDE IMPACT SENSOR ).
2. NO: Go to Step 4.
STEP 4. 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.
Q: Is the check result normal?
1. YES: Go to Step 5.
2. NO: Repair the wiring harness.
STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is stored.
1. Erase the DTC.
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is stored.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC B1408 or B1409 stored?
1. YES: Replace SRS-ECU (Refer to SRS CONTROL UNIT (SRS-ECU) ).
2. NO: Intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).