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

WARNING: This page is about a different car, the 2006 Mercury Milan, 2006 Lincoln Zephyr, and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: When installing a new restraints control module (RCM), always make sure the correct RCM is being installed. The RCM 40-pin connector is keyed differently for vehicles with side air curtains and side air bags than the 40-pin connector for vehicles without side air curtains and side air bags. Do not force the 40-pin connector onto the RCM. If the connector is forced onto the RCM, damage to the RCM and/or connector will occur.

NOTE: Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and Verification before proceeding with the Pinpoint Test.

S1 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: 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/Retrieve and Record Continuous Memory DTCs.
- Was on-demand DTC C1946 retrieved?
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.

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.
S2 CHECK CIRCUIT RR137 (BU/GY) 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: RCM C310a and C310b.
- Disconnect: 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).
  
  Fig 1: Checking Circuit RR137 (BU/GY) For Open Between RCM And Driver Seat
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 0.5 ohm?
Yes : GO to S3.

No : REPAIR circuit RR137 (BU/GY). GO to S7.
S3 CHECK CIRCUIT GD127 (BK/BU) FOR AN OPEN TO GROUND
- Measure the resistance between driver seat track position sensor C356-1, circuit GD127 (BK/BU) and ground.
  
  Fig 2: Checking Circuit GD127 (BK/BU) For Open To Ground
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 0.5 ohm?
Yes : GO to S4.

No : REPAIR circuit GD127 (BK/BU). GO to S7.
S4 CHECK THE SEAT TRACK POSITION SENSOR
- Connect: RCM C310a and C310b.
- Install a known good 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/Retrieve and Record Continuous Memory DTCs.
- Was on-demand DTC C1946 retrieved?
Yes : GO to S5.

No : Fault corrected. GO to S7.
S5 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.
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
- Reinstall the original 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/Retrieve and Record Continuous Memory DTCs.
- Was on-demand DTC C1946 retrieved?
Yes : INSTALL and CONFIGURE a new RCM. REFER to RESTRAINTS CONTROL MODULE (RCM) . GO to S7.

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 S7.
S6 CHECK FOR AN INTERMITTENT FAULT
- Key in OFF position.
- If equipped with seat side air bag:
  - Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DEPOWERING AND REPOWERING .
  - Disconnect driver seat side air bag module C327.
  - Connect restraint system tool 418-133 to driver seat side air bag module C327.
  - 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/Retrieve and Record Continuous Memory DTCs.
- Was on-demand DTC C1946 retrieved?
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.

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 S7.
S7 CHECK FOR ADDITIONAL DTCs
- Refer to the continuous memory DTCs recorded during Step S1.
- Were any continuous memory DTCs retrieved during Step S1 ?
Yes : Do not clear any DTCs until all DTCs have been resolved. GO to the SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DIAGNOSTIC TROUBLE CODE (DTC) TABLE 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 OCS module and RCM DTCs.