Pinpoint Test W: LFC 49/DTC C1981 - Seat Track Position Sensor Circuit Fault
WARNING: This page is about a different car, the 2005 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.
- 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.
- Enter the following diagnostic mode on the diagnostic tool: Retrieve/Record Continuous DTCs.
- Was DTC C1981 retrieved during the on-demand self test?
- 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 .
- 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 .
- Key in ON position.
- Measure the voltage between seat track position sensor C356 pin 2, circuit 1520 (LG), harness side and ground.
- Is the voltage less than 0.2 volt?
- W3 CHECK CIRCUIT 1520 (LG) FOR AN OPEN
- Key in OFF position.
- Depower the system. Refer to SUPPLEMENTAL RESTRAINT SYSTEM SRS DEPOWERING AND REPOWERING .
- Measure the resistance between RCM C310b pin 23, circuit 1520 (LG), harness side and driver seat C356 pin 2, circuit 1520 (LG), harness side.
- Is the resistance less than 0.5 ohm?
- W4 CHECK CIRCUIT 1203 (BK/LB) FOR AN OPEN
- Measure the resistance between seat track position sensor C356 pin 1, circuit 1203 (BK/LB), harness side and ground.
- Is the resistance less than 0.5 ohm?
- W5 CHECK THE SEAT TRACK POSITION SENSOR
- Install a known good seat track position sensor. Refer to SEAT POSITION SENSOR - POWER SEAT TRACK or SEAT POSITION SENSOR - MANUAL SEAT TRACK .
- Connect: RCM C310a and C310b.
- 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 diagnostic tool: On-Demand Self Test.
- Was DTC C1981 retrieved during the on-demand self test?
- 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.
- 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 diagnostic tool: On-Demand Self Test.
- Was DTC C1981 retrieved during the on-demand self test?
- Yes : INSTALL a new RCM. REFER to RESTRAINTS CONTROL MODULE RCM . GO to W8.
- 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.
- W7 CHECK FOR AN INTERMITTENT FAULT
- Key in OFF position.
- Enter the following diagnostic mode on the diagnostic tool: On-Demand Self Test.
- Was DTC C1981 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 W2.
- 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.
- W8 CHECK FOR ADDITIONAL DTCs
- Refer to the continuous DTCs recorded during Step W1.
- Were any continuous DTCs retrieved during Step W1 ?
- Yes : Do not clear any DTCs until all DTCs have been resolved. GO to the RESTRAINTS CONTROL MODULE RCM 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 DTCs.