B2909
PINPOINT TEST 27: DTC B2909
Normal Operation
The Belt Tension Sensor (BTS) operates in conjunction with the Occupant Classification Sensor (OCS) system. The OCS system interprets a variable voltage signal provided by the BTS to identify the possible presence of a child safety seat in the front passenger seat. The voltage output of the BTS 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 Occupant Classification System Module (OCSM) monitors the pressure sensor, BTS and all circuitry for faults. If the OCSM detects a fault on any of the BTS circuits, it will store DTC B2909 in memory and send a message to the Restraints Control Module (RCM), which will store DTC B00A0:09 in memory and send a message to the Instrument Cluster (IC) to illuminate the air bag warning indicator.The OCS system components (seat wiring harness, seat cushion frame, seat cushion foam pad, bladder with pressure sensor and OCSM) 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 BTS. If a new OCS system, OCS system component or seat cushion foam pad are needed, a new OCS system service kit must be installed as an assembly.
NOTE:Fault PIDs that end in OD indicate an on-demand status and are associated with on-demand DTC B2909. Fault PIDs that end in CM indicate continuous memory status and are associated with continuous DTC B2909.
Possible Causes
- Wiring, terminals or connectors
- BTS (part of RH front safety belt retractor)
- OCSM
Diagnostic Procedure
WARNING:Never probe the electrical connectors on air bag, safety canopy or side air curtain modules. Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.
WARNING:Never probe the electrical connectors on safety belt buckle/retractor pretensioners or adaptive load limiting retractors. Failure to follow this instruction may result in the accidental deployment of the safety belt pretensioners or adaptive load limiting retractors, which increases the risk of serious personal injury or death.
CAUTION:Use the correct probe adapter(s) when taking measurements. Failure to use the correct probe adapter(s) may damage the connector.
CAUTION:Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test.
NOTE:The Supplemental Restraint System (SRS) components should only be disconnected or reconnected when instructed to do so within a pinpoint test step. Failure to follow this instruction may result in incorrect diagnosis of the SRS.
NOTE:The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
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