B1B70

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.





(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. Check the front impact sensor.

(1)Disconnect the negative battery terminal.

(2)A front impact sensor is checked in the following way.

- Replace the front impact sensor (LH) {In case of code B1B70 (Regardless of "Active" or "Stored" faults)} with new part.

- Replace the front impact sensor (RH) {In case of code B1B71 (Regardless of "Active" or "Stored" faults)} with new part.

(3)Connect the negative battery terminal.

(4)After erasing the diagnostic trouble code memory, check the diagnostic trouble code again.

Q. Is either DTC No. B1B70 or B1B71 set?

YES Go to Step 3.
NO The procedure is complete.
STEP 3. Check the SRS-ECU.

(1)Disconnect the negative battery terminal.

(2)Replace the SRS-ECU with a new one (Refer to Service and Repair).

(3)Connect the negative battery terminal.

(4)Check the diagnostic trouble code again.

Q. Is either DTC No. B1B70 or B1B71 set?

YES Return to Step 1.
NO The procedure is complete.