B1409
DTC B1409: Front Impact Sensor (RH) (Squib) for Communication SystemFront Impact Sensor Circuit:
CAUTION: If DTC B1408 or B1409 is set in the SRS-ECU, always diagnose the CAN main bus line.
CIRCUIT OPERATION
The side 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 side-airbags should be deployed, it sends a fire signal to the SRS-ECU to deploy the side-airbags. In addition, the CPU diagnoses the internal components of the side 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 side impact sensor (RH) and the SRS-ECU is not possible or faulty.
TROUBLESHOOTING HINTS
- Damaged wiring harnesses or connectors
- Malfunction of the side impact sensor (RH)
- Malfunction of the SRS-ECU
DIAGNOSIS
Required Special Tool:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A (Vehicles with CAN communication system)
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
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.
1. Connect scan tool MB991958. Refer to "How to connect the scan tool." Reading 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 (Refer to Diagnosis). Component Tests and General Diagnostics
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 (Refer to How to Cope with Intermittent Malfunction).
STEP 3. Check for any diagnostic trouble code. (Using scan tool MB991958, read the diagnostic trouble code.)
Check the side impact sensor (RH).
1. Disconnect the negative battery terminal.
2. Replace the side impact sensor (RH) with the side impact sensor (LH).
3. Connect the negative battery terminal.
4. Erase diagnostic trouble code from memory, and check the diagnostic trouble code.
Q: Is DTC B1418 or B1419 set?
YES: Replace the side impact sensor (RH) with a new one. Go to Step 5.
NO: Go to Step 4.
STEP 4. Check the harness wires for open circuit or short circuit between SRS-ECU connector C-121 (terminal No.47 and 48) and side impact sensor (RH) connector A-27 (terminal No.1 and 2).
NOTE: After inspecting intermediate connectors C-22 and C-11 inspect the wiring harness. If the intermediate connectors C-22 and C-11 is damaged, repair or replace it.
Q: Are the harness wires between SRS-ECU connector C-121 (terminal No.47 and 48) and side impact sensor (RH) connector A-27 (terminal No.1 and 2) in good condition?
YES: Erase the diagnostic trouble code memory, and check the diagnostic trouble code. If DTC B1408 or B1409 sets, replace the SRS-ECU. Then go to Step 5.
NO: Replace the harness wires between SRS-ECU connector C-121 and side impact sensor (RH) connector A-27. Then go to Step 5.
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 DTC B1408 or B1409 set?
YES: Return to Step 1.
NO: The procedure is complete.