Pinpoint Test Be: DTC B2909 - Belt Tension Sensor Fault

NOTE: To identify between a production OCS system and a service OCS system (OCS service kit) inspect the OCS electronic control unit (ECU) electrical connector. A production OCS system allows disconnection of the electrical connector from the OCS ECU. A service OCS system (OCS service kit) has the OCS ECU electrical connector glued to the ECU, 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.

BE1 CHECK FOR CONTINUOUS OR ON-DEMAND DTCs
WARNING: Restraint system diagnostic tools are for service only. Tools must be removed prior to operating the vehicle over the road. Failure to remove restraint system diagnostic tools could result in injury and possible violation of vehicle safety standards.

WARNING: Never probe the connectors on the air bag module. Doing so can result in air bag deployment, which can result in personal injury.

WARNING: The safety belt pretensioner is a pyrotechnic device. Always wear safety glasses when repairing an air bag equipped vehicle and when handling a safety belt buckle pretensioner or safety belt retractor pretensioner. Never probe a pretensioner electrical connector. Doing so could result in pretensioner or air bag deployment and could result in personal injury.

NOTE: After diagnosing or repairing an SRS, the restraint system diagnostic tools must be removed before operating the vehicle over the road.

NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
- Enter the following diagnostic mode on the scan tool: On-Demand Self Test.
- Enter the following diagnostic mode on the scan tool: Retrieve/Record Continuous DTCs.
- Was DTC B2909 retrieved during the on-demand self test?
- Yes : This is a hard fault. The fault condition is still present. This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the on-demand self test.
  Vehicles with a production OCS system, GO to BE2 . Vehicles with a service OCS system, GO to BE9 .
- No : This is an intermittent fault. The fault condition is not present at this time. GO to BE13.
BE2 CHECK THE BELT TENSION SENSOR CIRCUITS FOR A SHORT TO VOLTAGE - PRODUCTION OCS SYSTEM
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Disconnect: RCM C2041a and C2041b.
- Disconnect: Passenger Side Air Bag Module C312e From Passenger Seat C312 (Vehicles equipped with side air bags).
- Connect: Restraint System Diagnostic Tool 501-109 to Passenger Seat C312e (Vehicles equipped with side air bags).
- Disconnect: Belt Tension Sensor C389.
- Disconnect: OCS ECU C3043.
- Repower the system. Do not prove out the system at this time. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Key in ON position.
- Measure the voltage between OCS ECU C3043 pin B, circuit 7-JA59 (YE/RD), harness side and ground; pin C, circuit 9-JA59 (BN/RD), harness side and ground; and pin A, circuit 8-JA59 (WH/RD), harness side and ground.
  
  Fig 1: Checking Belt Tension Sensor Circuits For A Short To Voltage - Production OCS System
  Courtesy of FORD MOTOR CO.
- Are the voltages less than 0.2 volt?
- Yes : GO to BE3.
- No : REPAIR circuit 7-JA59 (YE/RD), circuit 8-JA59 (WH/RD) or circuit 9-JA59 (BN/RD). GO to BE14.
BE3 CHECK THE BELT TENSION SENSOR CIRCUITS FOR AN OPEN - PRODUCTION OCS SYSTEM
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Measure the resistance between OCS ECU C3043 pin B, circuit 7-JA59 (YE/RD), harness side and belt tension sensor C389 pin 1, circuit 7-JA59 (YE/RD), harness side; and between OCS ECU C3043 pin C, circuit 9-JA59 (BN/RD), harness side and belt tension sensor C389 pin 2, circuit 9-JA59 (BN/RD), harness side; and between the OCS ECU C3043 pin A, circuit 8-JA59 (WH/RD), harness side and belt tension sensor C389 pin 3, circuit 8-JA59 (WH/RD), harness side.
  
  Fig 2: Checking Belt Tension Sensor Circuits For An Open - Production OCS System
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 0.5 ohm?
- Yes : GO to BE4.
- No : REPAIR circuit 7-JA59 (YE/RD), circuit 8-JA59 (WH/RD) or circuit 9-JA59 (BN/RD). GO to BE14.
BE4 CHECK CIRCUITS 7-JA59 (YE/RD), 8-JA59 (WH/RD) and 9-JA59 (BN/RD) FOR A SHORT TO GROUND - PRODUCTION OCS SYSTEM
- Measure the resistance between OCS ECU C3043 pin B, circuit 7-JA59 (YE/RD), harness side and ground; and between OCS ECU C3043 pin A, circuit 8-JA59 (WH/RD) harness side and ground; and between OCS ECU C3043 pin C, circuit 9-JA59 (BN/RD), harness side and ground.
  
  Fig 3: Checking Circuits 7-JA59 (YE/RD), 8-JA59 (WH/RD) And 9-JA59 (BN/RD) For A Short To Ground - Production OCS System
  Courtesy of FORD MOTOR CO.
- Are the resistances greater than 10,0000 ohms?
- Yes : GO to BE5.
- No : REPAIR circuit 7-JA59 (YE/RD), circuit 8-JA59 (WH/RD) or circuit 9-JA59 (BN/RD). GO to BE14.
BE5 CHECK CIRCUITS 7-JA59 (YE/RD), 8-JA59 (WH/RD) AND 9-JA59 (BN/RD) FOR A SHORT - PRODUCTION OCS SYSTEM
- Measure the resistance between OCS ECU C3043:
  - Pin B, circuit 7-JA59 (YE/RD), harness side and pin A, circuit 8-JA59 (WH/RD), harness side.
  - Pin B, circuit 7-JA59 (YE/RD), harness side and pin C, circuit 9-JA59 (BN/RD), harness side.
  - Pin A, circuit 8-JA59 (WH/RD), harness side and pin C, circuit 9-JA59 (BN/RD), harness side.
  Fig 4: Checking Circuits 7-JA59 (YE/RD), 8-JA59 (WH/RD) And 9-JA59 (BN/RD) For A Short - Production OCS System
  Courtesy of FORD MOTOR CO.
- Are the resistances greater than 10,0000 ohms?
- Yes : GO to BE6.
- No : REPAIR circuit 7-JA59 (YE/RD), circuit 9-JA59 (BN/RD) and/or circuit 8-JA59 (WH/RD). GO to BE14.
BE6 CHECK THE OCS ECU OUTPUT - PRODUCTION OCS SYSTEM
- Connect: OCS ECU C3043.
- Repower the system. Do not prove out the system at this time. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Key in ON position.
- Measure the voltage between belt tension sensor C389 pin 1, circuit 7-JA59 (YE/RD), harness side and pin 2, circuit 9-JA59 (BN/RD), harness side.
  
  Fig 5: Checking OCS ECU Output - Production OCS System
  Courtesy of FORD MOTOR CO.
- Is the voltage approximately 5 volts?
- Yes : GO to BE7.
- No : INSTALL a new OCS service kit. Refer to OCCUPANT CLASSIFICATION SENSOR . GO to BE14.
BE7 CHECK THE BELT TENSION SENSOR SIGNAL VOLTAGE OUTPUT - PRODUCTION OCS SYSTEM
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Connect a fused jumper lead between belt tension sensor C389 pin 1, circuit 7-JA59 (YE/RD), harness side and pin 1, circuit 7-JA59 (YE/RD), component side.
- Connect a fused jumper lead between belt tension sensor C389 pin 2, circuit 9-JA59 (BN/RD), harness side and pin 2, circuit 9-JA59 (BN/RD), component side.
- Repower the system. Do not prove out the system at this time. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Key in ON position.
- Measure the voltage between belt tension sensor C389 pin 3, circuit 8-JA59 (WH/RD), component side and ground as you vary the tension of the belt tension sensor.
  
  Fig 6: Checking Belt Tension Sensor Signal Voltage Output - Production OCS System
  Courtesy of FORD MOTOR CO.
- Does the 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 BE8.
- No : INSTALL a new passenger safety belt buckle and belt tension sensor assembly. Refer to SAFETY BELT SYSTEM . GO to BE14.
BE8 CONFIRM THE BELT TENSION SENSOR FAULT - PRODUCTION OCS SYSTEM
NOTE: Make sure all restraint system diagnostic tools, sensor electrical connectors and the RCM electrical connectors are connected before carrying out the on-demand self test. If not, erroneous DTCs will be recorded.
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Connect: Belt Tension Sensor C389.
- Repower the system. Do not prove out the system at this time. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Enter the following diagnostic mode on the scan tool: On-Demand Self Test.
- Was DTC B2290 retrieved during the on-demand self test?
- Yes : This is a hard fault. The fault condition is still present. This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the on-demand self test.
  INSTALL a new OCS system service kit. Refer to OCCUPANT CLASSIFICATION SENSOR . GO to BE14.
- No : CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition key frequently. ACTIVATE other systems in the same wire harness. REPAIR any intermittent concerns found. GO to BE14.
BE9 CHECK THE SEAT WIRING AND CONNECTORS - OCS SERVICE KIT
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Carry out a thorough visual inspection of the OCS system wiring and the belt tension sensor wiring terminals and connectors.
- Were any problems noted?
- Yes : REPAIR the seat connectors and wiring as needed. GO to BE14.
- No : GO to BE10.
BE10 CHECK THE OCS ECU OUTPUT - OCS SERVICE KIT
- Disconnect: Belt Tension Sensor C389.
- Repower the system. Do not prove out the system at this time. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Key in ON position.
- Measure the voltage between belt tension sensor C389 pin 1, circuit 7-JA59 (YE/RD), harness side and pin 2, circuit 9-JA59 (BN/RD), harness side.
  
  Fig 7: Checking OCS ECU Output - OCS Service Kit
  Courtesy of FORD MOTOR CO.
- Is the voltage approximately 5 volts?
- Yes : GO to BE11.
- No : INSTALL a new OCS service kit. Refer to OCCUPANT CLASSIFICATION SENSOR . GO to BE14.
BE11 CHECK THE BELT TENSION SENSOR SIGNAL VOLTAGE OUTPUT - OCS SERVICE KIT
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Connect a fused jumper lead between belt tension sensor C389 pin 1, circuit 7-JA59 (YE/RD), harness side and pin 1, circuit 7-JA59 (YE/RD), component side.
- Connect a fused jumper lead between belt tension sensor C389 pin 2, circuit 9-JA59 (BN/RD), harness side and pin 2, circuit 9-JA59 (BN/RD), component side.
- Repower the system. Do not prove out the system at this time. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Key in ON position.
- Measure the voltage between belt tension sensor C389 pin 3, circuit 8-JA59 (WH/RD), component side and ground as you vary the tension of the belt tension sensor.
  
  Fig 8: Measuring Voltage Between Belt Tension Sensor C389 Pin 3, Circuit 8-JA59 (WH/RD), Component Side And Ground
  Courtesy of FORD MOTOR CO.
- Does the 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 BE12.
- No : INSTALL a new passenger safety belt buckle and belt tension sensor assembly. Refer to SAFETY BELT SYSTEM . GO to BE14.
BE12 CONFIRM THE BELT TENSION SENSOR FAULT - OCS SERVICE KIT
NOTE: Make sure all restraint system diagnostic tools, sensor electrical connectors and the RCM electrical connectors are connected before carrying out the on-demand self test. If not, erroneous DTCs will be recorded.
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Connect: Belt Tension Sensor C389.
- Repower the system. Do not prove out the system at this time. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Enter the following diagnostic mode on the scan tool: On-Demand Self Test.
- Was DTC B2290 retrieved during the on-demand self test?
- Yes : This is a hard fault. The fault condition is still present. This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the on-demand self test.
  INSTALL a new OCS system service kit. Refer to OCCUPANT CLASSIFICATION SENSOR . GO to BE14.
- No : CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition key frequently. ACTIVATE other systems in the same wire harness. REPAIR any intermittent concerns found. GO to BE14.
BE13 CHECK FOR AN INTERMITTENT FAULT
- Key in OFF position.
- Enter the following diagnostic mode on the scan tool: On-Demand Self Test.
- Was DTC B2909 retrieved during the on-demand self test?
- Yes : This is a hard fault. The fault condition is now present. This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the on-demand self test.
  Vehicles with a production OCS system, GO to BE2 . Vehicles with a service OCS system, GO to BE2 .
- No : CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition key frequently. ACTIVATE other systems in the same wire harness. REPAIR any intermittent concerns found. GO to BE14.
BE14 CHECK FOR ADDITIONAL DTCs
- refer to the continuous DTCs recorded during Step BE1.
- Were any continuous DTCs retrieved during Step BE1?
- Yes : Do not clear any DTCs until all DTCs have been resolved. GO to the Restraints Control Module (RCM) Diagnostic Trouble Code (DTC) Table for pinpoint test direction.
- No : RECONNECT the system. If previously directed to deactivate the system, REACTIVATE the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEACTIVATION AND REACTIVATION . REPOWER the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING . PROVE OUT the system. CLEAR all DTCs.