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Home >> Mercury >> 2008 >> Milan Base, 2.3 Z, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 1232 (Supplemental Restraint System) >> Diagnostic Tests >> Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) >> Pinpoint Tests >> Pinpoint Test T: LFC 16/DTC B2909 - Belt Tension Sensor Fault >> Pinpoint Test T: LFC 16/DTC B2909 - Belt Tension Sensor Fault

Pinpoint Test T: LFC 16/DTC B2909 - Belt Tension Sensor Fault

WARNING: This page is about a different car, the 2009 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.
WARNING: Remove restraint system diagnostic tools from the vehicle prior to road testing. If tools are not removed, the supplemental restraint system (SRS) device may not deploy in a crash. Failure to follow this instruction may result in serious personal injury or death in a crash and possibly violate vehicle safety standards.
WARNING: Never probe the electrical connectors on air bag, safety canopy 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 probe the electrical connectors on safety belt buckle/retractor pretensioners or adaptive load limiting retractors. 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.
NOTE: 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.
NOTE: The supplemental restraint system (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.
NOTE: 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: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test.
  1. T1 CHECK FOR CONTINUOUS AND ON-DEMAND DTCs 
    • Enter the following diagnostic mode on the diagnostic tool: Self Test - RCM
    • Enter the following diagnostic mode on the diagnostic tool: DataLogger - RCM - View and Record All 2909 Fault PIDs
      • Refer to PID list in Normal Operation to view B2909 fault PIDs.
    • Do any on-demand DTC B2909 fault PIDs indicate a fault? 
    1. 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.

      Using the fault PIDs recorded, go to the appropriate pinpoint test step.

      For 2909_31_OD (Front Passenger Side Belt Tension Sensor Circuit Fault), go to  T2.

      For 2909_29_OD (Front Passenger Side Belt Tension Sensor Short to Ground), go to  T4.

    2. NO  : This is an intermittent fault when present as a continuous memory DTC only (DTC not retrieved on demand). The fault condition is not present at this time. Go to  T9.
  2. T2 CHECK THE BELT TENSION SENSOR CIRCUITS FOR A SHORT TO VOLTAGE 
    • Key in OFF position.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Disconnect: Passenger Seat Side Air Bag C337
    • Connect: Restraint System Diagnostic Tool 418-133 to Passenger Seat Side Air Bag C337
    • Disconnect: Belt Tension Sensor C3238
    • Disconnect: OCSM C3043
    • Repower the SRS. Do not  prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Key in ON position.
      • Fig 1: Checking Belt Tension Sensor Circuits For A Short To Voltage
      GF0002198Courtesy of FORD MOTOR CO.
    • Measure the voltage between OCSM:
      • C3043-11, circuit 2088 (TN/RD), harness side and ground
      • C3043-13, circuit 2090 (DB/OG), harness side and ground
      • C3043-12, circuit 2089 (OG/BK), harness side and ground.
    • Is voltage present on any circuit? 
    1. YES  : REPAIR circuit 2088 (TN/RD), 2089 (OG/BK) or 2090 (DB/OG). Go to  T10.
    2. NO  : Go to  T3.
  3. T3 CHECK THE BELT TENSION SENSOR CIRCUITS FOR AN OPEN 
    • Key in OFF position.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
      • Fig 2: Checking Belt Tension Sensor Circuits For An Open
      GF0046284Courtesy of FORD MOTOR CO.
    • Measure the resistance between OCSM C3043, harness side and belt tension sensor C3238, harness side using the following chart.
      OCSM Circuit Belt Tension Sensor
      C3043-11 2088 (TN/RD) C3238-1
      C3043-13 2090 (DB/OG) C3238-2
      C3043-12 2089 (OG/BK) C3238-3
    • Are the resistances less than 0.5 ohm? 
    1. YES  : Go to  T5.
    2. NO  : REPAIR circuit 2088 (TN/RD), 2089 (OG/BK) or 2090 (DB/OG).

      Go to  T10.

  4. T4 CHECK THE BELT TENSION SENSOR CIRCUITS FOR A SHORT TO GROUND 
    • Key in OFF position.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Disconnect: Passenger Seat Side Air Bag C337
    • Connect: Restraint System Diagnostic Tool 418-133 to Passenger Seat Side Air Bag C337
    • Disconnect: OCSM C3043
      • Fig 3: Checking Belt Tension Sensor Circuits For A Short To Ground
      GF0002200Courtesy of FORD MOTOR CO.
    • Measure the resistance between OCSM:
      • C3043-11, circuit 2088 (TN/RD), harness side and ground.
      • C3043-12, circuit 2089 (OG/BK), harness side and ground.
      • C3043-13, circuit 2090 (DB/OG), harness side and ground.
    • Are the resistances greater than 10,000 ohms? 
    1. YES  : Go to  T5.
    2. NO  : REPAIR circuit 2088 (TN/RD), 2089 (OG/BK) or 2090 (DB/OG). Go to  T10.
  5. T5 CHECK FOR A SHORT BETWEEN OCSM CIRCUITS 2088 (TN/RD), 2089 (OG/BK) AND 2090 (DB/OG) 
      Fig 4: Checking For A Short Between OCSM Circuits 2088 (TN/RD), 2089 (OG/BK) & 2090 (DB/OG)
      GF0046285Courtesy of FORD MOTOR CO.
    • Measure the resistance between the OCSM C3043, harness side using the following chart:
      OCSM OCSM
      C3043-11, circuit 2088 (TN/RD) C3043-12, circuit 2089 (OG/BK)
      C3043-11, circuit 2088 (TN/RD) C3043-13, circuit 2090 (DB/OG)
      C3043-12, circuit 2089 (OG/BK) C3043-13, circuit 2090 (DB/OG)
    • Are the resistances greater than 10,000 ohms? 
    1. YES  : Go to  T6.
    2. NO  : REPAIR circuit 2088 (TN/RD), 2089 (OG/BK) or 2090 (DB/OG). Go to  T10.
  6. T6 CHECK THE OCSM OUTPUT 
    • Connect: OCSM C3043
    • Repower the SRS. Do not  prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Key in ON position.
      • Fig 5: Checking OCSM Output
      GF0002202Courtesy of FORD MOTOR CO.
    • Measure the voltage between belt tension sensor C3238-1, circuit 2088 (TN/RD), harness side and C3238-2, circuit 2090 (DB/OG), harness side.
    • Is voltage approximately 5 volts? 
    1. YES  : Go to  T7.
    2. NO  : INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor . Go to  T10.
  7. T7 CHECK THE BELT TENSION SENSOR VOLTAGE OUTPUT 
    • Key in OFF position.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Connect a fused jumper lead between belt tension sensor C3238-1, circuit 2088 (TN/RD), harness side and pin 1, circuit 2088 (TN/RD), component side.
    • Connect a fused jumper lead between belt tension sensor C3238-2, circuit 2090 (DB/OG), harness side and pin 2, circuit 2090 (DB/OG), component side.
    • Repower the SRS. Do not  prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Key in ON position.
      • Fig 6: Checking Belt Tension Sensor Voltage Output
      GF0002203Courtesy of FORD MOTOR CO.
    • Measure the voltage between belt tension sensor C3238-3, circuit 2089 (OG/BK), component side and ground as you vary the tension of the belt tension sensor by pulling on the safety belt webbing near the anchor of the safety belt.
    • 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? 
    1. YES  : Go to  T8.
    2. NO  : INSTALL a new belt tension sensor (part of safety belt and retractor assembly). REFER to Front Safety Belt Retractor in SAFETY BELT SYSTEM . Go to  T10.
  8. T8 CONFIRM THE BELT TENSION SENSOR FAULT 
    NOTE: Make sure all restraint system diagnostic tools, sensor electrical connectors and the RCM electrical connector are connected before carrying out the on-demand self test. If not, erroneous DTCs will be recorded.
    1. YES  : INSTALL a new OCS system service kit. REFER to Occupant Classification Sensor . Go to  T10.
    2. 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. 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.  REPAIR any intermittent wiring, terminal or connector concerns found. Go to  T10.
  9. T9 CHECK FOR AN INTERMITTENT FAULT 
    • Enter the following diagnostic mode on the diagnostic tool: Self Test - RCM
    • Enter the following diagnostic mode on the diagnostic tool: DataLogger - RCM - View and Record All 2909 Fault PIDs
      • Refer to PID list in Normal Operation to view B2909 fault PIDs.
    • Do any on-demand DTC B2909 fault PIDs indicate a fault? 
    1. 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.

      Using the fault PIDs recorded, go to the appropriate pinpoint test step.

      For 2909_31_OD (Front Passenger Side Belt Tension Sensor Circuit Fault), go to  T2.

      For 2909_29_OD (Front Passenger Side Belt Tension Sensor Short to Ground), go to  T4.

    2. 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. 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.  REPAIR any intermittent wiring, terminal or connector concerns found. Go to  T10.
  10. T10 CHECK FOR ADDITIONAL SRS DTCs 
    • Key in OFF position.
      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).
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: Self Test - RCM
    • Are any RCM DTCs retrieved indicating a fault? 
    1. YES  : Do not clear any DTCs until all DTCs have been resolved. Go to the Supplemental Restraint System (SRS) DTC Chart  for pinpoint test direction.
    2. NO  : CLEAR all RCM continuous memory DTCs. PROVE OUT the SRS. Repair is complete. RETURN the vehicle to the customer.
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