Pinpoint Tests AS: DTC B2909

Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)

Pinpoint Tests

Pinpoint Test AS: DTC B2909

Refer to Wiring Diagram Set 46, Supplemental Restraint System for schematic and connector information. Diagrams By Number

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, 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) module to illuminate the air bag warning indicator.

a 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.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- BTS (part of RH front safety belt retractor assembly)
- OCSM

PINPOINT TEST AS: DTC B2909

WARNING: Never probe the electrical connectors on air bag, Safety Canopy(R) 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 disassemble or tamper with safety belt buckle/retractor pretensioners or adaptive load limiting retractors or probe the electrical connectors. 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.

NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when taking measurements. Failure to use the correct probe adapter(s) may damage the connector.

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

NOTE: 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: Always make sure the correct SRS 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 Catalog Advantage(TM) or equivalent to make sure the correct component is being installed. If an incorrect SRS component is installed, DTCs may set.

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

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AS1 RETRIEVE OCSM DTCs

- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - OCSM.
- Enter the following diagnostic mode on the scan tool: DataLogger - OCSM - View and Record All 2909 Fault PIDs.
- Refer to PID list in Normal Operation to view 2909 fault PIDs.
- Do any on-demand 2909 fault PIDs indicate a fault?

Yes
This fault cannot be cleared until it is corrected and the DTC is no longer retrieved on-demand during self-test.

Using the on-demand fault PIDs recorded, GO to the appropriate pinpoint test step.

For fault PID 2909_31_OD, GO to AS2.

For fault PID 2909_28_OD, GO to AS8.

For fault PID 2909_30_OD, GO to AS9.

For fault PID 2909_29_OD, GO to AS10.

No
This is an intermittent fault. The DTC Status information indicates the fault was not present at time of request. GO to AS14.

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AS2 CHECK THE BTS CIRCUITS FOR A SHORT TO VOLTAGE

- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: Passenger Seat Bulkhead Connector.
- Disconnect: BTS C389.
- Disconnect: OCSM C3159.
- Repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Measure the voltage between OCSM:
- C3159-11, circuit 7-JA59 (YE/RD), harness side and ground.
- C3159-12, circuit 8-JA59 (WH/RD), harness side and ground.

- Is voltage present on either circuit?

Yes
REPAIR circuit 7-JA59 (YE/RD) or 8-JA59 (WH/RD). GO to AS15.

No
GO to AS3.

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AS3 CHECK THE BTS CIRCUITS FOR AN OPEN

- Ignition OFF.
- Measure the resistance between OCSM C3159, harness side and BTS C389, harness side using the following chart.

- Are the resistances less than 0.5 ohm?

Yes
GO to AS4.

No
REPAIR the affected circuit.

GO to AS15.

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AS4 CHECK THE BTS CIRCUITS FOR A SHORT TO GROUND

- Measure the resistance between OCSM:
- C3159-11, circuit 7-JA59 (YE/RD), harness side and ground.
- C3159-12, circuit 8-JA59 (WH/RD), harness side and ground.

- Are the resistances greater than 10,000 ohms?

Yes
GO to AS5.

No
REPAIR circuit 7-JA59 (YE/RD) or 8-JA59 (WH/RD). GO to AS15.

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AS5 CHECK FOR A SHORT BETWEEN CIRCUITS

- Measure the resistance between BTS C389-1, circuit 7-JA59 (YE/RD), harness side and C389-2, circuit 8-JA59 (WH/RD), harness side.

- Is the resistance greater than 10,000 ohms?

Yes
GO to AS6.

No
REPAIR the affected circuits. GO to AS11.

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AS6 CHECK THE OCSM OUTPUT

- Connect: OCSM C3159.
- Ignition ON.
- Measure the voltage between BTS C389-1 , circuit 7-JA59 (YE/RD), harness side and C389-3, circuit 9-JA59 (BN/RD), harness side.

- Is voltage approximately 5 volts?

Yes
GO to AS7.

No
INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor Service and Repair. GO to AS15.

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AS7 CHECK THE BTS VOLTAGE OUTPUT

- Ignition OFF.
- Connect a fused jumper lead between BTS C389-1, circuit 7-JA59 (YE/RD), harness side and pin 1, circuit 7-JA59 (YE/RD), component side.
- Connect a fused jumper lead between BTS C389-3, circuit 9-JA59 (BN/RD), harness side and pin 3, circuit 9-JA59 (BN/RD), component side.
- Ignition ON.
- Measure the voltage between BTS C389-2, circuit 8-JA59 (WH/RD), component side and ground while varying the tension of the BTS by pulling upward at the safety belt webbing.

- Is any voltage present?

Yes
REPAIR the affected circuit. GO to AS15.

No
GO to AS13.

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AS9 CHECK THE BTS CIRCUITS FOR AN OPEN

- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: BTS C389.
- Disconnect: OCSM C3159.
- Measure the resistance between OCSM C3159, harness side and BTS C389, harness side using the following chart.

- Are the resistances less than 0.5 ohm?

Yes
GO to AS11.

No
REPAIR circuit 8-JA59 (WH/RD), 7-JA59 (YE/RD) or 9-JA59 (BN/RD). GO to AS15.

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AS10 CHECK THE BTS CIRCUITS FOR A SHORT TO GROUND

- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: BTS C389.
- Disconnect: OCSM C3159.
- Measure the resistance between BTS:
- C389-2, circuit 8-JA59 (WH/RD), harness side and ground.
- C389-1, circuit 7-JA59 (YE/RD), harness side and ground.

- Are the resistances greater than 10,000 ohms?

Yes
GO to AS13.

No
REPAIR circuit 8-JA59 (WH/RD) or 7-JA59 (YE/RD). GO to AS15.

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AS11 CHECK THE OCSM OUTPUT

- Connect: OCSM C3159 (if disconnected previously).
- Disconnect: BTS C389 (if not previously disconnected).
- If previously directed to depower the SRS, repower the SRS. Do notprove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Measure the voltage between BTS C389-1, circuit 7-JA59 (YE/RD), harness side and C389-3, circuit 9-JA59 (BN/RD), harness side.

- Is the voltage approximately 5 volts?

Yes
GO to AS12.

No
INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor Service and Repair. GO to AS15.

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AS12 CHECK THE BTS VOLTAGE OUTPUT

- Ignition OFF.
- Connect a fused jumper lead between BTS C389-1, circuit 7-JA59 (YE/RD), harness side and pin 1, circuit 7-JA59 (YE/RD), component side.
- Connect a fused jumper lead between BTS C389-3, circuit 9-JA59 (BN/RD), harness side and pin 3, circuit 9-JA59 (BN/RD), component side.
- Ignition ON.
- Measure the voltage between BTS C389-2, circuit 8-JA59 (WH/RD), component side and ground while varying the tension of the BTS by pulling upward at the safety belt webbing.

- Does voltage vary from approximately 0.95 volt with no tension applied to the sensor, to approximately 3.8 volts with full tension applied to the sensor?

Yes
GO to AS13.

No
INSTALL a new passenger safety belt retractor assembly. REFER to Restraint Systems. GO to AS15.

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AS13 CONFIRM THE BTS FAULT

NOTE: Make sure all OCS system components, restraint system sensor electrical connectors and the RCM electrical connectors are connected before carrying out the self-test. If not, DTCs will be recorded.

- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Prior to reconnecting any previously disconnected SRS component:
- inspect connector(s) (including any in-line connectors) for pushed-out, loose or spread terminals and loose or frayed wire connections at terminals.
- inspect wire harness for any damage, pinched, cut or pierced wires.
- inspect RCM C310A and C310B Connector Position Assurance (CPA) lever/lock for correct operation. Refer to Restraints Control Module (RCM) Service and Repair.
- repair any concerns found.
Refer to Wiring Diagram Set 5, Connector Repair Procedures for schematic and connector information. Diagrams By Number

- Connect: OCSM C3159 (if disconnected previously).
- Connect: BTS C389.
- Repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - OCSM.
- Enter the following diagnostic mode on the scan tool: DataLogger - OCSM - View and Record All 2909 Fault PIDs.
- Refer to PID list in Normal Operation to view 2909 fault PIDs.
- Does the original on-demand 2909 fault PID indicate a fault?

Yes
INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor Service and Repair. GO to AS15.

No
In the process of diagnosing the fault, the fault condition has become intermittent. Do not install any new SRS components at this time. SRS components should only be installed when directed to do so in the pinpoint test. GO to AS14.

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AS14 CHECK FOR AN INTERMITTENT FAULT

- Ignition OFF.
- Disconnect: BTS C389.
- Disconnect: OCSM.
- Inspect for the following:
- inspect harness and component connectors for loose or spread terminals and loose or frayed wire connections at terminals.
- inspect wire harness for any damage, pinched, cut or pierced wires.
- repair any concerns found.
Refer to Wiring Diagram Set 5, Connector Repair Procedures for schematic and connector information. Diagrams By Number

- Connect: All Previously Disconnected Component(s)/Connector(s).
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - OCSM.
- Enter the following diagnostic mode on the scan tool: DataLogger - OCSM - View and Record All 2909 Fault PIDs.
- Refer to PID list in Normal Operation to view 2909 fault PIDs.
- Do any on-demand 2909 fault PIDs indicate a fault?

Yes
The fault condition is now present. Do not clear any DTCs until all DTC concerns have been resolved.

Using the on-demand fault PIDs recorded, GO to the appropriate pinpoint test step.

For fault PID 2909_31_OD, GO to AS2.

For fault PID 2909_28_OD, GO to AS8.

For fault PID 2909_30_OD, GO to AS9.

For fault PID 2909_29_OD, GO to AS10.

No
The fault is not present and cannot be recreated at this time. Do not install any new SRS components at this time. SRS components should only be installed when directed to do so in the pinpoint test. GO to AS15.

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AS15 CHECK FOR ADDITIONAL SRS DTCs

- Ignition OFF.
- WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
- Reconnect all SRS components (if previously disconnected).
- If previously directed to depower the SRS, repower the SRS. Do notprove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - Restraints.
- NOTE: When selecting Restraints from the Self Test menu, DTCs will be retrieved from the RCM and OCSM.
- Does the status information for any RCM DTC indicate a fault is present and/or are any OCSM on-demand DTCs retrieved?

Yes
Do not clear any DTCs until all DTC concerns have been resolved. GO to the DTC Charts for pinpoint test direction. Diagnostic Trouble Code Tests and Associated Procedures

No
CLEAR all RCM and OCSM DTCs. PROVE OUT the SRS. Repair is complete. RETURN the vehicle to the customer.

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