Test U: LFC 16/DTC B2909 - Belt Tension Sensor Fault

PINPOINT TEST U: LFC 16/DTC B2909 - BELT TENSION SENSOR FAULT

U1-U2:

U2-U4:

U4-U6:

U6-U8:

U8-U10:

NOTE: LFC 16 is shared between DTC B2290 and DTC B2909.

Normal Operation
The belt tension sensor is part of the occupant classification sensor (OCS) system. The OCS system interprets a variable voltage signal provided by the safety belt tension sensor to identify the possible presence of a child safety seat in the front passenger seat. The voltage output of the belt tension sensor is proportional to the amount of tension applied to the sensor by the belt, no tension low voltage (approximately 0.95 volt), high tension high voltage (approximately 3.8 volts).

The OCS system checks the belt tension sensor circuits for faults. If the OCS detects one of the following faults on any of the belt tension sensor circuits, it will report the failure to the RCM. The RCM will store diagnostic trouble code (DTC) B2909 in memory and flash either lamp fault code (LFC) 16 (or higher priority code if one exists) on the air bag indicator.

The OCS system components (seat cushion foam pad, bladder with pressure sensor and electronic control unit) are calibrated to each other and are serviced as an assembly. The OCS system components are not to be installed separately with the exception of the belt tension sensor. If a new OCS system, OCS system component or seat cushion foam pad are needed, a new OCS system service kit (seat cushion foam pad, bladder with pressure sensor and electronic control unit) must be installed as an assembly.

Possible Causes
A belt tension sensor circuit fault can be caused by:
- damaged wiring, terminals or connectors.
- a faulted belt tension sensor.
- a faulted OCS ECU.