Pinpoint Test N: LFC 52/DTC B2438 - Passenger Safety Belt Buckle Switch Circuit Short To Ground: Overview

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.

N1 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 B2438 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 N2.
- No : This is an intermittent fault. The fault condition is not present at this time. GO to N6.
N2 CHECK CIRCUIT 8-JA55 (WH/BK) FOR A SHORT TO GROUND BETWEEN THE RCM AND PASSENGER SEAT
- Key in OFF position.
- Depower the system. refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING in this article.
- Disconnect: Passenger Seat C313.
- Disconnect: RCM C310b.
- Measure the resistance between RCM C310b pin 26, circuit 8-JA55 (WH/BK), harness side and ground.
  
  Fig 1: Checking Circuit 8-JA55 (WH/BK) For A Short To Ground Between The RCM And Passenger Seat
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 1,000,000 ohms?
- Yes : GO to N3.
- No : REPAIR circuit 8-JA55 (WH/BK) in the body wiring harness. GO to N7.
N3 CHECK CIRCUIT 8-JA55 (WH/BK) FOR A SHORT TO GROUND BETWEEN THE PASSENGER SAFETY BELT BUCKLE SWITCH AND GROUND
- Connect: Passenger Seat C313.
- Disconnect: Passenger Safety Belt Buckle Switch C3066.
- Measure the resistance between passenger safety belt buckle switch C3066 pin 1, circuit 8-JA55 (WH/BK), harness side and ground.
  
  Fig 2: Checking Circuit 8-JA55 (WH/BK) For A Short To Ground Between The Passenger Safety Belt Buckle Switch And Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 1,000,000 ohms?
- Yes : GO to N4.
- No : REPAIR circuit 8-JA55 (WH/BK) in the seat wiring harness. GO to N7.
N4 CHECK THE PASSENGER SAFETY BELT BUCKLE SWITCH
- Connect: RCM C310b.
- Install a known good passenger 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 B2438 retrieved during the on-demand self test?
- Yes : GO to N5.
- No : Fault corrected. GO to N7.
N5 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 passenger 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 B2438 retrieved during the on-demand self test?
- Yes : INSTALL a new RCM. REFER to RESTRAINTS CONTROL MODULE (RCM) . GO to N7.
- 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 N7.
N6 CHECK FOR AN INTERMITTENT FAULT
- Key in OFF position.
- Enter the following diagnostic mode on the diagnostic tool: On-Demand Self Test.
- Was DTC B2438 retrieved during the on-demand self test?
- Yes : GO to N2.
- 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 N7.
N7 CHECK FOR ADDITIONAL DTCs
- Refer to the continuous DTCs recorded during Step N1.
- Were any continuous DTCs retrieved during Step N1 ?
- 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.