Seat Belt Buckle: Description and Operation

Seat Belt Buckle







The two front seat belt buckles, which contain hall sensors to detect whether the seat belt is engaged in the buckle or not, are connected in different ways depending on the model year:
- Model year 1999-2002: The two front seat belt buckles are directly connected to the central electronic module (CEM). This transmits the information onwards on the controller area network (CAN) to the supplemental restraint system module (SRS).
- Model year 2003-: The two front seat belt buckles are directly connected to the supplemental restraint system module (SRS).

The information is used to set the activation level for the airbags and decides whether to activate the seat belt tensioners or not. If a fault is detected in the seat belt buckles or in the terminal for the seat belt buckles, the activation level of the airbags for both the driver and passenger is set as if the occupant is not wearing a seat belt. The seat belt tensioner will still function as if the occupant is wearing a seat belt however.

NOTE: Applies to model year 1999-2002. In the event of a fault, either in the hall sensor or in the wiring for the front seat belt buckles, a diagnostic trouble code (DTC) is stored locally in the central electronic module (CEM). This diagnostic trouble code (DTC) is stored at the same time as a diagnostic trouble code (DTC) is stored in the Supplemental Restraint System Module (SRS). The diagnostic trouble code (DTC) in the supplemental restraint system module (SRS) cannot be erased before the fault has been remedied and the diagnostic trouble code (DTC) has been erased from the central electronic module (CEM).