Pinpoint Test L: LFC 42/DTC B2296 - Restraint System Impact Sensor Fault

WARNING: This page is about a different car, the 2005 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.

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

L1 CHECK FOR A HARD OR INTERMITTENT DTC
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 diagnostic tool: On-Demand Self Test.
- Enter the following diagnostic mode on the diagnostic tool: Flag DTC B2296/Record All Flagged Faults.
- Enter the following diagnostic mode on the diagnostic tool: Retrieve/Flag/Record Continuous DTCs.
- Was DTC B2296 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.
  If a flagged fault of "?" was recorded, multiple faults exist and the entire pinpoint test must be carried out.
  
  For front impact severity sensor (FNT_SEN) with a mounting/communications (COMM) fault, GO to L2.
  
  For front impact severity sensor (FNT_SEN) with an internal fault (INT) fault, INSTALL a new front impact severity sensor. REFER to FRONT IMPACT SEVERITY SENSOR . GO to L14.
- No : This is an intermittent fault. The fault condition is not present at this time. GO to L13.
L2 INSPECT THE FRONT IMPACT SEVERITY SENSOR MOUNTING, MOUNTING BRACKET AND MOUNTING SURFACE
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM SRS DEPOWERING AND REPOWERING .
- Access the front impact severity sensor. Refer to FRONT IMPACT SEVERITY SENSOR .
- Inspect the front impact severity sensor for:
  - Loose electrical connector.
  - Loose sensor mounting bolt.
- Remove the front impact severity sensor.
- Visually inspect the front impact severity sensor, alignment tabs, electrical connector and mounting surface for damage, corrosion or dirt.
- Was a significant amount of corrosion or dirt found, or was the front impact severity sensor mounting bracket attached to the mounting surface incorrectly or was the front impact severity sensor bolt not fully seated and tightened correctly?
- Yes : CLEAN, TIGHTEN bolt or REPAIR the mounting surface as necessary. REINSTALL the front impact severity sensor. GO to L14.
- No : GO to L3.
L3 INSTALL THE FRONT IMPACT SEVERITY SENSOR AND CARRY OUT THE ON-DEMAND SELF TEST
- Clean and repair the mounting surface as necessary.
- Clean the front impact severity sensor mounting bolt.
- Install the front impact severity sensor. Refer to FRONT IMPACT SEVERITY SENSOR .
- 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 diagnostic tool: On-Demand Self Test.
- Enter the following diagnostic mode on the diagnostic tool: Flag DTC B2296/Record All Flagged Faults.
- Was DTC B2296 retrieved during the on-demand self test?
- Yes : GO to L4.
- No : Fault corrected. GO to L14.
L4 CHECK THE FRONT IMPACT SEVERITY SENSOR GROUND CIRCUIT 618 (PK/LG) FOR HIGH RESISTANCE
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM SRS DEPOWERING AND REPOWERING .
- Disconnect: Front Impact Severity Sensor C177.
- Measure the resistance between front impact severity sensor C177 pin 1, circuit 618 (PK/LG), harness side and front impact severity sensor case ground.
  
  Fig 1: Checking Front Impact Severity Sensor Ground Circuit 618 (PK/LG) For High Resistance
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 100 ohms?
- Yes : GO to L6.
- No : GO to L5.
L5 CLEAN THE FRONT IMPACT SEVERITY SENSOR MOUNTING SURFACE AND CARRY OUT THE ON-DEMAND SELF TEST
- Remove the front impact severity sensor. Refer to FRONT IMPACT SEVERITY SENSOR .
- Clean and repair the mounting surface as necessary.
- Clean the front impact severity sensor mounting bolt.
- Install the front impact severity sensor. Refer to FRONT IMPACT SEVERITY SENSOR .
- 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 diagnostic tool: On-Demand Self Test.
- Enter the following diagnostic mode on the diagnostic tool: Flag DTC B2296/Record All Flagged Faults.
- Was DTC B2296 retrieved during the on-demand self test?
- Yes : GO to L6.
- No : Fault corrected. GO to L14.
L6 CHECK CIRCUIT 617 (PK/OG) AND CIRCUIT 618 (PK/LG) FOR A SHORT TO VOLTAGE BETWEEN THE RCM AND THE FRONT IMPACT SEVERITY SENSOR
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM SRS DEPOWERING AND REPOWERING .
- Disconnect: Front Impact Severity Sensor C177.
- Disconnect: RCM C310a and C310b.
- 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 front impact severity sensor C177 pin 2, circuit 617 (PK/OG), harness side and ground; and between front impact severity sensor C177 pin 1, circuit 618 (PK/LG), harness side and ground.
  
  Fig 2: Checking Circuit 617 (PK/OG) And Circuit 618 (PK/LG) For Short To Voltage Between RCM And Front Impact Severity Sensor
  Courtesy of FORD MOTOR CO.
- Are the voltages less than 0.2 volt?
- Yes : GO to L7.
- No : REPAIR circuit 617 (PK/OG) or circuit 618 (PK/LG). GO to L14.
L7 CHECK CIRCUIT 617 (PK/OG) AND CIRCUIT 618 (PK/LG) FOR A SHORT TO GROUND BETWEEN THE RCM AND THE FRONT IMPACT SEVERITY SENSOR
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM SRS DEPOWERING AND REPOWERING .
- Measure the resistance between front impact severity sensor C177 pin 2, circuit 617 (PK/OG), harness side and ground; and between front impact severity sensor C177 pin 1, circuit 618 (PK/LG), harness side and ground.
  
  Fig 3: Checking Circuit 617 (PK/OG) And Circuit 618 (PK/LG) For Short To Ground Between RCM And Front Impact Severity Sensor
  Courtesy of FORD MOTOR CO.
- Are the resistances greater than 1,000,000 ohms?
- Yes : GO to L8.
- No : REPAIR circuit 617 (PK/OG) or 618 (PK/LG) circuit. GO to L14.
L8 CHECK CIRCUIT 617 (PK/OG) FOR AN OPEN BETWEEN THE RCM AND THE FRONT IMPACT SEVERITY SENSOR
- Measure the resistance between RCM C310b pin 19, circuit 617 (PK/OG), harness side and front impact severity sensor C177 pin 2, circuit 617 (PK/OG), harness side.
  
  Fig 4: Checking Circuit 617 (PK/OG) For An Open Between RCM And Front Impact Severity Sensor
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 0.5 ohm?
- Yes : GO to L9.
- No : REPAIR circuit 617 (PK/OG). GO to L14.
L9 CHECK CIRCUIT 618 (PK/LG) FOR AN OPEN BETWEEN THE RCM AND THE FRONT IMPACT SEVERITY SENSOR
- Measure the resistance between RCM C310b pin 20, circuit 618 (PK/LG), harness side and front impact severity sensor C177 pin 1, circuit 618 (PK/LG), harness side.
  
  Fig 5: Checking Circuit 618 (PK/LG) For An Open Between RCM And Front Impact Severity Sensor
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 0.5 ohm?
- Yes : GO to L10.
- No : REPAIR circuit 618 (PK/LG). GO to L14.
L10 CHECK CIRCUIT 617 (PK/OG) FOR A SHORT TO CIRCUIT 618 (PK/LG) BETWEEN THE RCM AND THE FRONT IMPACT SEVERITY SENSOR
- Measure the resistance between C177 pin 2, circuit 617 (PK/OG), harness side and front impact severity sensor C177 pin 1, circuit 618 (PK/LG), harness side.
  
  Fig 6: Checking Circuit 617 (PK/OG) For Short To Circuit 618 (PK/LG) Between RCM And Front Impact Severity Sensor
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 1,000,000 ohms?
- Yes : GO to L11.
- No : REPAIR circuit 617 (PK/OG) and circuit 618 (PK/LG). GO to L14.
L11 CHECK THE FRONT IMPACT SEVERITY SENSOR
- Connect: RCM C310a and C310b.
- Install a known good front impact severity sensor.
- 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 diagnostic tool: On-Demand Self Test.
- Enter the following diagnostic mode on the diagnostic tool: Flag DTC B2296/Record All Flagged Faults.
- Were any faults flagged against the front impact severity sensor?
- Yes : GO to L12.
- No : Fault corrected. GO to L14.
L12 CONFIRM THE RCM 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.
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM SRS DEPOWERING AND REPOWERING .
- Install the original front impact severity sensor.
- 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 diagnostic tool: On-Demand Self Test.
- Enter the following diagnostic mode on the diagnostic tool: Flag DTC B2296/Record All Flagged Faults.
- Was DTC B2296 retrieved during the on-demand self test?
- Yes : If a "?" was flagged by the diagnostic tool, CARRY OUT the entire pinpoint test.
  INSTALL a new RCM. GO to L14.
- 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.
L13 CHECK FOR AN INTERMITTENT FAULT
- Key in OFF position.
- Enter the following diagnostic mode on the diagnostic tool: On-Demand Self Test.
- Enter the following diagnostic mode on the diagnostic tool: Flag DTC B2296/Record All Flagged Faults.
- Was DTC B2296 retrieved during the on-demand self test?
- Yes : This is a hard fault. The fault condition is now present. The fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the on-demand self test.
  If a flagged fault of "?" was recorded, multiple faults exist and the entire pinpoint test must be carried out.
  
  For front impact severity sensor (FNT_SEN) with a mounting/communications (COMM) fault, GO to L2.
  
  For front impact severity sensor (FNT_SEN) with an internal fault (INT) fault, INSTALL a new front impact severity sensor. REFER to FRONT IMPACT SEVERITY SENSOR . GO to L14.
- No : VISUALLY INSPECT the affected impact sensor, mounting brackets and mounting surface for damage, corrosion or dirt. INSPECT the wiring, terminals and connectors for damage, corrosion or dirt. 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 L14.
L14 CHECK FOR ADDITIONAL DTCs
- Refer to the continuous DTCs recorded during Step L1.
- Were any continuous DTCs retrieved during Step L1 ?
- 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.