Pinpoint Test AY: Passenger Seat Occupant Classification Sensor "C": Notes

Refer to appropriate Supplemental Restraint System in OEM Wiring Diagrams article, for schematic and connector information.

Normal Operation and Fault Conditions

The Belt Tension Sensor (BTS) operates in conjunction with the OCS. The OCS interprets a variable voltage signal provided by the Belt Tension Sensor (BTS) to identify the possible presence of a child safety seat in the front passenger seat. The voltage output of the Belt Tension Sensor (BTS) is proportional to the amount of tension applied to the sensor by the belt: no belt tension causes a low voltage (approximately 0.95 volt) to be output and high belt tension causes a high voltage (approximately 3.8 volts) to be returned to the OCSM. The OCSM monitors the Belt Tension Sensor (BTS) reference voltage circuit for a short to voltage or a short to ground.

If a fault is detected, the OCSM stores DTC B00C2:11 or B00C2:12 in memory and sends a message to the RCM over the HS-CAN2 indicating that an OCS fault is present. Upon receipt of this message, the RCM sets DTC B00A0:09 and sends a message to the IPC to illuminate the airbag warning indicator.

PPT AY OCSM DTC FAULT TRIGGER CONDITIONS

DTC

Description

Fault Trigger Conditions

Possible Causes

Wiring, terminals or connectors
Belt Tension Sensor (BTS) (part of RH front passenger seatbelt buckle)
OCSM

Visual Inspection and Diagnostic Pre-checks

Inspect for a damaged passenger seatbelt buckle or Belt Tension Sensor (BTS).
Inspect for a damaged passenger seat cushion wiring harness.
Inspect for a loose or damaged OCSM or Belt Tension Sensor (BTS) connector.
Inspect for a damaged OCSM.

WARNING: Incorrect repair techniques or actions can cause an accidental SRS deployment. Never compromise or depart from these instructions. Failure to precisely follow all instructions could result in serious personal injury from an accidental deployment.

CAUTION: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.

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

NOTE: Only disconnect or reconnect SRS components when instructed to do so within a pinpoint test step. Failure to follow this instruction may result in incorrect diagnosis of the SRS.

NOTE: Always make sure the correct OCSM component is being installed. Parts released for other vehicles may not be compatible even if they appear physically similar. Check the part number listed in the Ford parts catalog to make sure the correct component is being installed. If an incorrect OCSM component is installed, DTCs may set.

NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.

Passenger Seatbelt Buckle Connector - C3238

Circuit	Pin
BTS VREF (Belt Tension Switch Voltage Reference) - LR142	2(YELLOW/BLUE)

Occupant Classification System Module (OCSM) Connector - C3159

Circuit