B2909

Step 1:

Step 2-Step 3:

Step 4-Step 6:

Step 7:

Step 8:

Step 9:

Step 10-Step 11:

Step 12-Step 13:

Step 14-Step 15:

Step 16-Step 17:

Step 18:

Step 19:

Step 20- Step 21:

PINPOINT TEST 16: DTC B2909 - BELT TENSION SENSOR FAULT

Normal Operation
The belt tension sensor operates in conjunction with 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 restraints control module (RCM). The RCM will store diagnostic trouble code (DTC) B2909 in memory and illuminate the air bag indicator.

The OCS system components (seat wiring harness, seat cushion frame, 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, seat wiring harness 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 system.

NOTE: To identify between a production OCS system and an OCS system service kit (OCS service kit), inspect the OCS module electrical connector.

A production OCS system allows the disconnect of the electrical connector from the OCS module.

An OCS system service kit has the OCS module electrical connector glued to the module. It cannot and should not be disconnected or altered.

NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough Inspection and Verification before proceeding with the pinpoint test.