Pinpoint Test M: LFC 51/DTC B2435 - Driver Safety Belt Buckle Switch Circuit Resistance Out Of Range

WARNING: This page is about a different car, the 2005 Lincoln LS. 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.

M1 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.

WARNING: Never probe the electrical connector on a side air curtain module. Doing so can result in side air curtain deployment.

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: Retrieve/Record Continuous DTCs.
- Enter the following diagnostic mode on the diagnostic tool: On-Demand Self Test.
- Was DTC B2435 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 DTC is no longer retrieved during the on-demand self test.
  GO to M2.
- No : This is an intermittent fault. The fault condition is not present at this time. GO to M8.
M2 CHECK CIRCUIT 8-JA54 (WH) FOR AN OPEN BETWEEN THE RCM AND DRIVER SEAT
- Key in OFF position.
- Depower the system. refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING in this article.
- Disconnect: Driver Seat C315.
- Disconnect: RCM C310b.
- Measure the resistance between RCM C310b pin 25, circuit 8-JA54 (WH), harness side and driver seat C315 pin 11, circuit 8-JA54 (WH), harness side.
  
  Fig 1: Checking Circuit 8-JA54 (WH) For Open Between RCM And Driver Seat
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 0.5 ohm?
- Yes : GO to M3.
- No : REPAIR circuit 8-JA54 (WH) in the body wiring harness. GO to M9.
M3 CHECK CIRCUIT 31-JA54 (BK/YE) FOR AN OPEN BETWEEN AND DRIVER SEAT AND GROUND
- Measure the resistance between C315 pin 4, circuit 31-JA54 (BK/YE), harness side and ground.
  
  Fig 2: Measuring Resistance Between C315 Pin 4, Circuit 31-JA54 (BK/YE) And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to M4.
- No : REPAIR circuit 31-JA54 (BK/YE) in the body wiring harness. GO to M9.
M4 CHECK CIRCUIT 8-JA54 (WH) FOR AN OPEN BETWEEN THE DRIVER SEAT AND DRIVER SAFETY BELT BUCKLE SWITCH
- Disconnect: Driver Safety Belt Buckle Switch C3065.
- Measure the resistance between driver seat C315 pin 11, circuit 8-JA54 (WH), harness side and driver safety belt buckle switch C3065 pin 1, circuit 8-JA54 (WH), harness side.
  
  Fig 3: Checking Circuit 8-JA54 (WH) For Open Between Driver Seat And Driver Safety Belt Buckle Switch
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 0.5 ohm?
- Yes : GO to M5.
- No : REPAIR circuit 8-JA54 (WH) in the seat wiring harness. GO to M9.
M5 CHECK CIRCUIT 31-JA54 (BK/YE) FOR AN OPEN BETWEEN THE DRIVER SEAT AND DRIVER SAFETY BELT BUCKLE SWITCH
- Measure the resistance between driver seat C315 pin 4, circuit 31-JA54 (BK/YE), harness side and driver safety belt buckle switch C3065 pin 2, circuit 31-JA54 (BK/YE), harness side.
  
  Fig 4: Checking Circuit 31-JA54 (BK/YE) For Open Between Driver Seat And Driver Safety Belt Buckle Switch
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 0.5 ohm?
- Yes : GO to M6.
- No : REPAIR circuit 31-JA54 (BK/YE) in the seat wiring harness. GO to M9.
M6 CHECK THE DRIVER SAFETY BELT BUCKLE SWITCH
- Connect: RCM C310b.
- Install a known good driver safety belt buckle. Refer to SAFETY BELT SYSTEM .
- Repower the system. Do not prove out the system at this time. refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING in this article.
- Enter the following diagnostic mode on the diagnostic tool: On-Demand Self Test.
- Was DTC B2435 retrieved during the on-demand self test?
- Yes : GO to M7.
- No : Fault corrected. GO to M9.
M7 CONFIRM 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 in this article.
- Reinstall the original driver safety belt buckle switch. Refer to SAFETY BELT SYSTEM .
- Repower the system. Do not prove out the system at this time. refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING in this article.
- Enter the following diagnostic mode on the diagnostic tool: On-Demand Self Test.
- Was DTC B2435 retrieved during the on-demand self test?
- Yes : INSTALL a new RCM. REFER to RESTRAINTS CONTROL MODULE (RCM) . GO to M9.
- 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. REPAIR any intermittent concerns found. GO to M9.
M8 CHECK FOR AN INTERMITTENT FAULT
- Key in OFF position.
- Enter the following diagnostic mode on the diagnostic tool: On-Demand Self Test.
- Was DTC B2435 retrieved during the on-demand self test?
- Yes : GO to M2.
- 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. REPAIR any intermittent concerns found. GO to M9.
M9 CHECK FOR ADDITIONAL DTCs
- Refer to the continuous DTCs recorded during Step M1.
- Were any continuous DTCs retrieved during Step M1 ?
- Yes : Do not clear any DTCs until all DTCs have been resolved. GO to the RESTRAINTS CONTROL MODULE (RCM) DIAGNOSTIC TROUBLE CODE (DTC) PRIORITY TABLE in this article for pinpoint test direction.
- No : RECONNECT the system. REPOWER the system. refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING in this article. PROVE OUT the system. CLEAR all DTCs.