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Home >> Mercury >> 2008 >> Milan Base, 2.3 Z, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 1401 (Supplemental Restraint System) >> Diagnosis And Testing >> Air Bag And Safety Belt PRETENSIONER Supplemental Restraint System (SRS) >> Pinpoint Tests >> Pinpoint Test S: DTC C1946 - Front Driver's Seat Track Position Switch Circuit Open >> Pinpoint Test S: DTC C1946 - Front Driver's Seat Track Position Switch Circuit Open

Pinpoint Test S: DTC C1946 - Front Driver's Seat Track Position Switch Circuit Open

WARNING: This page is about a different car, the 2009 Mercury Milan, 2009 Lincoln MKZ, and 2009 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
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.
NOTE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test.
NOTE: Supplemental restraint system (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: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
  1. S1 CHECK FOR CONTINUOUS AND ON-DEMAND DTCs 
    • Enter the following diagnostic mode on the diagnostic tool: Self Test - RCM
    • Was RCM on-demand DTC C1946 retrieved? 
    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. Go to  S2.
    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  S6.
  2. S2 CHECK CIRCUIT RR137 (BU/GY) FOR AN OPEN 
    • Key in OFF position.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Disconnect: Seat Track Position Sensor C356
    • Connect a fused jumper wire between driver seat track position sensor C356-2, circuit RR137 (BU/GY), harness side and C356-1, circuit GD127 (BK/BU), harness side.
    • Repower the SRS. Do not  prove out the system at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: Self Test - RCM
    • DIAGNOSTIC TIP:  When viewing on-demand DTCs with the driver seat track position sensor circuits shorted together, a short to ground fault would normally be retrieved.
    • Did the driver seat track position switch on-demand DTC change from indicating C1946 to C1947? 
    1. YES  : INSTALL a new seat track position sensor. REFER to Seat Position Sensor . Go to  S7.
    2. NO  : Go to  S3.
  3. S3 CHECK CIRCUIT RR137 (BU/GY) FOR AN OPEN 
    • Key in OFF position.
    • Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Disconnect: RCM C310a and C310b
    • Remover the jumper wire from the driver seat track position sensor C356.
    • Measure the resistance between RCM C310b-23, circuit RR137 (BU/GY), harness side and driver seat track position sensor C356-2, circuit RR137 (BU/GY), harness side.
    • Is the resistance less than 0.5 ohm? 
    1. YES  : Go to  S4.
    2. NO  : REPAIR circuit RR137 (BU/GY). Go to  S7.
  4. S4 CHECK CIRCUIT GD127 (BK/BU) FOR AN OPEN 
      Fig 1: Checking Circuit GD127 (BK/BU) For An Open
      GF0008834Courtesy of FORD MOTOR CO.
    • Measure the resistance between driver seat track position sensor C356-1, circuit GD127 (BK/BU) and ground.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  S5.
    2. NO  : REPAIR GD127 (BK/BU). Go to  S7.
  5. S5 CONFIRM THE RCM FAULT 
    NOTE: Make sure all restraint system components, sensor electrical connectors and the RCM electrical connectors are connected before carrying out the on-demand self test. If not, erroneous DTCs will be recorded.
    • Connect: Driver Seat Track Position Sensor C356
    • Connect: RCM C310a and C310b
    • Repower the SRS. Do not  prove out the system at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering .
    • Key in ON position.
    • Enter the following diagnostic mode on the diagnostic tool: Self Test - RCM
    • Was RCM on-demand DTC C1946 retrieved? 
    1. YES  : INSTALL a new RCM. REFER to Restraints Control Module (RCM) . Go to  S7.
    2. NO  : In the process of diagnosing the fault, the fault condition has become intermittent. CHECK for causes of the intermittent fault in the areas previously worked in, particularly the pins and terminals of electrical connectors that were disconnected. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition key frequently. 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  S7.
  6. S6 CHECK FOR AN INTERMITTENT 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. Go to  S2.
    2. NO  : The fault is not present and cannot be recreated at this time.

      CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition key frequently. 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  S7.

  7. S7 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 - Restraints
    • Are any RCM and/or OCSM 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 and OCSM DTCs. PROVE OUT the SRS. REPAIR is complete. RETURN the vehicle to the customer.
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