Test W: DTC B2909 - Belt Tension Sensor Fault

PINPOINT TEST W: DTC B2909 - BELT TENSION SENSOR FAULT

W1-W2:

W2-W4:

W4-W6:

W6-W8:

W8-W10:

Lamp Fault Codes (LFCs)







The lamp fault codes (LFCs) indicate the specific flagged faults associated with diagnostic trouble codes (DTC) B2909:

NOTE: The secondary warning chime will be activated along with the primary warning indicator when a fault is detected.

Normal Operation
The belt tension sensor operates in conjunction with the occupant classification sensor (OCS) system. The electronic control module (ECU) for 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 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.

The ECU monitors the belt tension sensor circuits for faults. If a fault is detected on any of the belt tension sensor circuits, it will report the failure to the restraints control module (RCM). The RCM will store DTC B2909 in memory and, depending on the fault, flash a LFC on the air bag indicator. The secondary air bag warning chime will also be activated.

Possible Causes
A belt tension sensor circuit fault can be caused by:
- wiring, terminals or connectors.
- an open circuit.
- a circuit short to voltage.
- a circuit short to ground.
- a faulted belt tension sensor.
- a faulted OCS ECU.