Pinpoint Test Ac: DTC C1946 - Driver Seat Track Position Switch Circuit Open

WARNING: This page is about a different car, the 2006 Mercury Grand Marquis and 2006 Ford Crown Victoria. 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.

AC1 CHECK FOR ON-DEMAND AND CONTINUOUS DTCs
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 scan tool: On-Demand Self Test.
- Enter the following diagnostic mode on the scan tool: Retrieve/Record Continuous DTCs.
- Was DTC C1946 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. GO to AC2.

No : This is an intermittent fault. The fault condition is not present at this time. GO to AC6.
AC2 CHECK CIRCUIT 1520 (LG) FOR AN OPEN BETWEEN THE RCM AND THE DRIVER SEAT
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Disconnect: Driver Seat Track Position Sensor C358.
- Disconnect: RCM C310a and C310b.
- Measure the resistance between RCM C310b-23, circuit 1520 (LG), harness side and driver seat track position sensor C358-2, circuit 1520 (LG), harness side.
  
  Fig 1: Measuring Resistance Between RCM C310B-23, Circuit 1520 And Driver Seat Track Position Sensor C358-2, Circuit 1520
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 0.5 ohm?
Yes : GO to AC3.

No : REPAIR circuit 1520 (LG). GO to AC7.
AC3 CHECK CIRCUIT 1558 (TN/BK) FOR AN OPEN BETWEEN THE RCM AND THE DRIVER SEAT
- Measure the resistance between RCM C310b-24, circuit 1558 (TN/BK), harness side and driver seat track position sensor C358-1, circuit 1558 (TN/BK), harness side.
  
  Fig 2: Measuring Resistance Between RCM C310b Pin 24, Circuit 1558 And Driver Seat C358 Pin 1, Circuit 1558
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 0.5 ohm?
Yes : GO to AC4.

No : REPAIR circuit 1558 (TN/BK). GO to AC7.
AC4 CHECK THE SEAT TRACK POSITION SENSOR
- Connect: RCM C310a and C310b.
- Install a known good driver seat track position sensor. Refer to SEAT POSITION SENSOR .
- Connect: Seat Track Position Sensor C358.
- 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.
- Enter the following diagnostic mode on the scan tool: On-Demand Self Test.
- Was DTC C1946 retrieved during the on-demand self test?
Yes : GO to AC5.

No : Fault corrected. GO to AC7.
AC5 CONFIRM THE RCM FAULT
NOTE: Make sure all restraint system diagnostic tools, 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.
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Reinstall the original driver seat track position 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 scan tool: On-Demand Self Test.
- Was DTC C1946 retrieved during the on-demand self test?
Yes : INSTALL a new RCM . REFER to RESTRAINTS CONTROL MODULE (RCM) . GO to AC7.

No : Fault corrected. GO to AC7.
AC6 CHECK FOR AN INTERMITTENT FAULT
- Key in OFF position.
- Enter the following diagnostic mode on the scan tool: On-Demand Self Test.
- Was DTC C1946 retrieved during the on-demand self test?
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 AC2.

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 AC7.
AC7 CHECK FOR ADDITIONAL DTCs
- Refer to the continuous DTCs recorded during Step AC1.
- Were any continuous DTCs retrieved during Step AC1 ?
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.

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.