B2909

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

Pinpoint Test AS: DTC B2909

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

Normal Operation

The Belt Tension Sensor (BTS) operates in conjunction with the Occupant Classification System (OCS) system. The OCS (Occupant Classification System) system interprets a variable voltage signal provided by the BTS (Belt Tension Sensor) to identify the possible presence of a child safety seat in the front passenger seat. The voltage output of the BTS (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 Occupant Classification System Module (OCSM) monitors the pressure sensor, BTS (Belt Tension Sensor) and all circuitry for faults. If the OCSM (Occupant Classification System Module) 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 (Belt Tension Sensor) (part of RH front safety belt retractor assembly)

- OCSM (Occupant Classification System Module)

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 seat belt deployable components, including pretensioners, load limiters and inflators. Never back probe deployable device electrical connectors. Tampering or back probing may cause an accidental deployment and result in 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 (Supplemental Restraint System).

NOTE: Always make sure the correct SRS (Supplemental Restraint System) 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 (Supplemental Restraint System) component is installed, DTCs may set.

NOTE: The SRS (Supplemental Restraint System) must be fully operational and free of faults before releasing the vehicle to the customer.

AS1 RETRIEVE OCSM (Occupant Classification System Module) DTCs

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: Self Test- OCSM (Occupant Classification System Module).

- Enter the following diagnostic mode on the scan tool: DataLogger- OCSM (Occupant Classification System Module)- View and Record All 2909 Fault PIDs.
- NOTE: Fault PIDs are only displayed in the DataLogger screen. The DTC status shown in the Self Test screen is not a fault PID and must not be used for diagnostic navigation in this test.
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.

AS2 CHECK THE BTS (Belt Tension Sensor) CIRCUITS FOR A SHORT TO VOLTAGE

- Ignition OFF.

- Depower the SRS (Supplemental Restraint System). Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.

- Disconnect: Passenger Seat Bulkhead Connector.

- Disconnect: BTS (Belt Tension Sensor) C389.

- Disconnect: OCSM (Occupant Classification System Module) C3159.

- Repower the SRS (Supplemental Restraint System). Do not prove out the SRS (Supplemental Restraint System) 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 (Occupant Classification System Module) :
- 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.

AS3 CHECK THE BTS (Belt Tension Sensor) CIRCUITS FOR AN OPEN

- Ignition OFF.

- Measure the resistance between OCSM (Occupant Classification System Module) C3159, harness side and BTS (Belt Tension Sensor) C389, harness side using the following chart.

OCSM (Occupant Classification System Module) Circuit BTS (Belt Tension Sensor) C3159-11 7-JA59 (YE/RD) C389-1 C3159-12 8-JA59 (WH/RD) C389-2 C3159-13 9-JA59 (BN/RD) C389-3

Are the resistances less than 0.5 ohm?

Yes
GO to AS4.

No
REPAIR the affected circuit.

GO to AS15.

AS4 CHECK THE BTS (Belt Tension Sensor) CIRCUITS FOR A SHORT TO GROUND

- Measure the resistance between OCSM (Occupant Classification System Module) :
- 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.

AS5 CHECK FOR A SHORT BETWEEN CIRCUITS

- Measure the resistance between BTS (Belt Tension Sensor) 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.

AS6 CHECK THE OCSM (Occupant Classification System Module) OUTPUT

- Connect: OCSM (Occupant Classification System Module) C3159.

- Ignition ON.

- Measure the voltage between BTS (Belt Tension Sensor) 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 (Occupant Classification System) system service kit. REFER to Occupant Classification Sensor . GO to AS15.

AS7 CHECK THE BTS (Belt Tension Sensor) VOLTAGE OUTPUT

- Ignition OFF.

- Connect a fused jumper lead between BTS (Belt Tension Sensor) 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 (Belt Tension Sensor) 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 (Belt Tension Sensor) C389-2, circuit 8-JA59 (WH/RD), component side and ground while varying the tension of the BTS (Belt Tension Sensor) by pulling upward at the safety belt webbing.

Is any voltage present?

Yes
REPAIR the affected circuit. GO to AS15.

No
GO to AS13.

AS9 CHECK THE BTS (Belt Tension Sensor) CIRCUITS FOR AN OPEN

- Ignition OFF.

- Depower the SRS (Supplemental Restraint System). Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.

- Disconnect: BTS (Belt Tension Sensor) C389.

- Disconnect: OCSM (Occupant Classification System Module) C3159.

- Measure the resistance between OCSM (Occupant Classification System Module) C3159, harness side and BTS (Belt Tension Sensor) C389, harness side using the following chart.

OCSM (Occupant Classification System Module) Circuit BTS (Belt Tension Sensor) C3159-11 7-JA59 (YE/RD) C389-1 C3159-12 8-JA59 (WH/RD) C389-2 C3159-13 9-JA59 (BN/RD) C389-3

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.

AS10 CHECK THE BTS (Belt Tension Sensor) CIRCUITS FOR A SHORT TO GROUND

- Ignition OFF.

- Depower the SRS (Supplemental Restraint System). Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.

- Disconnect: BTS (Belt Tension Sensor) C389.

- Disconnect: OCSM (Occupant Classification System Module) C3159.

- Measure the resistance between BTS (Belt Tension Sensor) :
- 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 AS11.

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

AS11 CHECK THE OCSM (Occupant Classification System Module) OUTPUT

- Connect: OCSM (Occupant Classification System Module) C3159 (if disconnected previously).

- Disconnect: BTS (Belt Tension Sensor) C389 (if not previously disconnected).

- If previously directed to depower the SRS (Supplemental Restraint System), repower the SRS (Supplemental Restraint System). Do not prove out the SRS (Supplemental Restraint System) 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 (Belt Tension Sensor) 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 (Occupant Classification System) system service kit. REFER to Occupant Classification Sensor . GO to AS15.

AS12 CHECK THE BTS (Belt Tension Sensor) VOLTAGE OUTPUT

- Ignition OFF.

- Connect a fused jumper lead between BTS (Belt Tension Sensor) 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 (Belt Tension Sensor) 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 (Belt Tension Sensor) C389-2, circuit 8-JA59 (WH/RD), component side and ground while varying the tension of the BTS (Belt Tension Sensor) 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. GO to AS15.

AS13 CONFIRM THE BTS (Belt Tension Sensor) FAULT

NOTE: Make sure all OCS (Occupant Classification System) system components, restraint system sensor electrical connectors and the RCM (Restraints Control Module) electrical connectors are connected before carrying out the self-test. If not, DTCs will be recorded.

- Ignition OFF.

- Depower the SRS (Supplemental Restraint System). Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.

- Prior to reconnecting any previously disconnected SRS (Supplemental Restraint System) 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 (Restraints Control Module) C310A and C310B Connector Position Assurance (CPA) lever/lock for correct operation. Refer to Restraints Control Module (RCM) .

- repair any concerns found.
Refer to Wiring Diagrams Set 5, Connector Repair Procedures for schematic and connector information. Electrical Diagrams

- Connect: OCSM (Occupant Classification System Module) C3159 (if disconnected previously).

- Connect: BTS (Belt Tension Sensor) C389.

- Repower the SRS (Supplemental Restraint System). Do not prove out the SRS (Supplemental Restraint System) 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 (Occupant Classification System Module).

- Enter the following diagnostic mode on the scan tool: DataLogger- OCSM (Occupant Classification System Module)- 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 (Occupant Classification System) system service kit. REFER to Occupant Classification Sensor . GO to AS15.

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

AS14 CHECK FOR AN INTERMITTENT FAULT

- Ignition OFF.

- Disconnect: BTS (Belt Tension Sensor) C389.

- Disconnect: OCSM (Occupant Classification System Module).

- 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 Diagrams Set 5, Connector Repair Procedures for schematic and connector information. Electrical Diagrams

- Connect: All Previously Disconnected Component(s)/Connector(s).

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: Self Test- OCSM (Occupant Classification System Module).

- Enter the following diagnostic mode on the scan tool: DataLogger- OCSM (Occupant Classification System Module)- 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 (Supplemental Restraint System) components at this time. SRS (Supplemental Restraint System) components should only be installed when directed to do so in the pinpoint test. GO to AS15.

AS15 CHECK FOR ADDITIONAL SRS (Supplemental Restraint System) 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 (Supplemental Restraint System) components (if previously disconnected).

- If previously directed to depower the SRS (Supplemental Restraint System), repower the SRS (Supplemental Restraint System). Do not prove out the SRS (Supplemental Restraint System) 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 (Restraints Control Module) and OCSM (Occupant Classification System Module).

Does the status information for any RCM (Restraints Control Module) DTC indicate a fault is present and/or are any OCSM (Occupant Classification System Module) 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. Air Bag Systems / Seat Belt Systems

No
CLEAR all RCM (Restraints Control Module) and OCSM (Occupant Classification System Module) DTCs. PROVE OUT the SRS (Supplemental Restraint System). Repair is complete. RETURN the vehicle to the customer.