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Home >> Mercury >> 2008 >> Milan Base, 3.0 1, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 734 (Supplemental Inflatable Restraint System - F-150 & Mark LT) >> Diagnostic Tests >> Pinpoint Tests - Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS) >> Pinpoint Tests >> Pinpoint Test W: LFC 49/DTC C1981 - Driver Seat Track Position Sensor Circuit Fault >> Pinpoint Test W: LFC 49/DTC C1981 - Seat Track Position Sensor Circuit Fault

Pinpoint Test W: LFC 49/DTC C1981 - Seat Track Position Sensor Circuit Fault

WARNING: This page is about a different car, the 2007 Lincoln Mark LT and 2007 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.
  1. W1 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/Retrieve and Record Continuous Memory DTCs
    • Was on-demand DTC C1981 retrieved? 
    1. 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  W2 .
    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  W7 .
  2. W2 CHECK CIRCUIT 1520 (LG) FOR A SHORT TO VOLTAGE 
    • Key in OFF position.
    • Depower the system. Refer to Supplemental Restraint System (SRS) Depowering and Repowering  in this article.
    • Disconnect: Driver Safety Belt Buckle Pretensioner C3201
    • Connect: Restraint System Diagnostic Tool 418-F395 to Driver Safety Belt Buckle Pretensioner C3201
    • Disconnect: RCM C310a and C310b
    • Disconnect: Driver Seat Track Position Sensor C356
    • Repower the system. Do not  prove out the system at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering  in this article.
    • Key in ON position.
    • Measure the voltage between seat track position sensor C356-2, circuit 1520 (LG), harness side and ground.
      • Fig 1: Checking Circuit 1520 (LG) For Short To Voltage
      GF0002210Courtesy of FORD MOTOR CO.
    • Is the voltage less than 0.2 volt? 
    1. YES  : Go to  W3.
    2. NO  : REPAIR circuit 1520 (LG). Go to  W8 .
  3. W3 CHECK CIRCUIT 1520 (LG) FOR AN OPEN 
    • Key in OFF position.
    • Depower the system. Refer to Supplemental Restraint System (SRS) Depowering and Repowering  in this article.
    • Measure the resistance between RCM C310b-23, circuit 1520 (LG), harness side and driver seat C356-2, circuit 1520 (LG), harness side.
      • Fig 2: Checking Circuit 1520 (LG) For An Open
      GF0002211Courtesy of FORD MOTOR CO.
    • Is the resistance less than 0.5 ohm? 
    1. YES  : Go to  W4.
    2. NO  : REPAIR circuit 1520 (LG). Go to  W8 .
  4. W4 CHECK CIRCUIT 1203 (BK/LB) FOR AN OPEN 
    • Measure the resistance between seat track position sensor C356-1, circuit 1203 (BK/LB), harness side and ground.
      • Fig 3: Checking Circuit 1203 (BK/LB) For Open
      GF0002212Courtesy of FORD MOTOR CO.
    • Is the resistance less than 0.5 ohm? 
    1. YES  : Go to  W5.
    2. NO  : REPAIR circuit 1203 (BK/LB). Go to  W8 .
  5. W5 CHECK THE SEAT TRACK POSITION SENSOR 
    1. YES  : Go to  W6.
    2. NO  : Fault corrected. Go to  W8 .
  6. W6 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.
    1. YES  : INSTALL a new RCM. REFER to Restraints Control Module (RCM)  in this article. Go to  W8 .
    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. REPAIR any intermittent concerns found. Go to  W8 .
  7. W7 CHECK FOR AN INTERMITTENT FAULT 
    • Key in OFF position.
    • Enter the following diagnostic mode on the diagnostic tool: On-Demand Self Test/Retrieve and Record Continuous Memory DTCs
    • Was on-demand DTC C1981 retrieved? 
    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.

      Go to  W2.

    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. REPAIR any intermittent concerns found. Go to  W8 .
  8. W8 CHECK FOR ADDITIONAL DTCs 
    • Refer to the continuous memory DTCs recorded during Step W1.
    • Were any continuous memory DTCs retrieved during Step W1? 
    1. YES  : Do not clear any DTCs until all DTCs have been resolved. Go to the Restraints Control Module (RCM) Diagnostic Trouble Code (DTC) Table in this article for pinpoint test direction.
    2. NO  : RECONNECT the system. If previously directed to deactivate the system, REACTIVATE the system. REFER to Supplemental Restraint System (SRS) Deactivation and Reactivation  in this article. REPOWER the system. REFER to Supplemental Restraint System (SRS) Depowering and Repowering  in this article. PROVE OUT the system. CLEAR all DTCs.
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