B1B71

DTC B1B70: Malfunction of G-sensor inside Front Impact Sensor (LH)
DTC B1B71: Malfunction of G-sensor inside Front Impact Sensor (RH)


CAUTION: If DTC B1B70 or B1B71 is set in the SRS-ECU, always diagnose the CAN main bus line.

DTC SET CONDITIONS
These DTCs are set if the following conditions are detected from the analog G-sensor inside the front impact sensor output:

- Analog G-sensor is not operating.
- Analog G-sensor characteristics are abnormal.
- Analog G-sensor output is abnormal.

TROUBLESHOOTING HINTS
Malfunction of front impact sensor (LH) (for DTC B1B70) and front impact sensor (RH) (for DTC B1B71)

DIAGNOSIS

Required Special Tool:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-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". Scan Tool Connecting
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 Controller area network Diagnosis).

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 general (body and chassis)-How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).

STEP 3. Check the front impact sensor.

Replace the front impact sensor (RH) or front impact sensor (LH) with a new one. Check the diagnostic trouble code.

Q: Is either DTC B1B70 or B1B71 set?

YES : Replace the SRS-ECU.

NO : The procedure is complete.