B1B72

DTC B1B72: Malfunction of G-sensor Inside Side Impact Sensor (LH)
DTC B1B75: Malfunction of G-sensor Inside Side Impact Sensor (RH)

CAUTION:
If the diagnostic trouble code B1B72 or B1B75 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 side 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 side impact sensor (LH) (for DTC B1B72) and side impact sensor (RH) (for DTC B1B75)

DIAGNOSTIC PROCEDURE

Required Special Tools:

- 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 side impact sensor.

(1)Disconnect the negative battery terminal.

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

- Replace the left side impact sensor {In case of code B1B72 (Regardless of "Active" or "Stored" faults)} with the new part.

- Replace the right side impact sensor {In case of code B1B75 (Regardless of "Active" or "Stored" faults)} with the 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. B1B72 or B1B75 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. B1B72 or B1B75 set?

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