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Home >> Lincoln >> 2018 >> MKZ Select, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1715 (Abs Guided Routine Testing) >> Pinpoint Tests >> Pinpoint Test B: Wheel Speed Sensor Erratic Signal Faults >> Possible Causes
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Possible Causes

WARNING: This page is about a different car, the 2018 Ford Focus. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.
  1. B1: CHECK FOR ABS MODULE DTCS 
    • Ignition ON, engine OFF.
    • Carry out the ABS self-test.
    • Is DTC C003x:01, C003x:11, C003x:12, C003x:14 or C1A95:01 present? 
    Yes No
    For DTC C0031:01, C0031:11, C0031:12, C0031:14, C0032:11, C0034:01, C0034:11, C0034:12, C0034:14, C0035:11 or C1A95:01, GO to PINPOINT TEST M .
    For DTC C0037:01, C0037:11, C0037:12, C0037:14, C0038:11, C003A:01, C003A:11, C003A:12, C003A:14 or C003B:11, GO to PINPOINT TEST N .    		 Go to  B2.
  2. B2: CHECK THE TIRES SIZE AND PRESSURE 
    • Ignition OFF.
    • Verify all the tires and wheels are the same size and the tire size and inflation pressures are correct as indicated on the VC label.
    • Are the tires and wheels OK? 
    Yes No
    Go to  B3. INSTALL the correct size tire or wheel or ADJUST tire pressure as necessary.
  3. B3: CHECK THE WHEEL SPEED SENSOR AND ELECTRICAL CONNECTOR 
    • With the transmission in NEUTRAL, position the vehicle on a hoist. Refer to JACKING AND LIFTING - OVERVIEW
    • Disconnect the suspect wheel speed sensor electrical connector.
    • Using a good light source, inspect the wheel speed sensor and electrical connector for the following:
      • corrosion - install new connector or terminal and clean the module pins
      • damaged or bent pins - install new terminals or pins
      • pushed-out pins - install new pins as necessary
      • spread terminals - install new terminals as necessary
      • water intrusion - clean and dry the connector, install a new connector as necessary
    • Inspect the wheel speed sensor and harness for abrasions, broken connector tabs or water intrusion.
    • Are the wheel speed sensor and harness OK? 
    Yes No
    Go to  B4. INSTALL a new wheel speed sensor for the one in question. REFER to the appropriate procedure in REMOVAL AND INSTALLATION .
  4. B4: INSPECT THE WHEEL SPEED SENSOR MOUNTING 
    • Inspect the suspect wheel speed sensor and fastener for looseness.
    • Inspect the suspect wheel speed sensor installation.
    • Is the wheel speed sensor installed correctly and is the wheel speed sensor fastener tight? 
    Yes No
    Go to  B5. REINSTALL or TIGHTEN the wheel speed sensor fastener to specification.
  5. B5: CHECK THE FRONT AND REAR ENCODERS FOR DAMAGE 
    • Are the wheel bearings and encoders OK? 
    Yes No
    Go to  B6. For the front wheel hub, INSTALL a new wheel hub and bearing as necessary. REFER to the appropriate procedure in FRONT SUSPENSION (EXCEPT ELECTRIC VEHICLE) . For the rear wheel hub, INSTALL a new wheel hub and bearing as necessary. REFER to the appropriate procedure in REAR SUSPENSION (EXCEPT ELECTRIC VEHICLE) .
  6. B6: CHECK THE WHEEL SPEED SENSOR CIRCUITS FOR AN OPEN 
    • Ignition OFF.
    • ABS Module connector disconnected.
    • Measure the circuits between the ABS module and the suspect wheel speed sensor.
    • Measure the resistance between:
      (+) ABS Module Connector, Harness Side (-) Left Front Wheel Speed Sensor Sensor Connector, Harness Side
      LF WSS HI LF WSS HI
      LF WSS LO LF WSS LO
    • Measure the resistance between:
      (+) ABS Module Connector, Harness Side (-) Right Front Wheel Speed Sensor Connector, Harness Side
      RF WSS HI RF WSS HI
      RF WSS LO RF WSS LO
    • Measure the resistance between:
      (+) ABS Module Connector, Harness Side (-) Left Rear Wheel Speed Sensor Connector, Harness Side
      LR WSS HI LR WSS HI
      LR WSS LO LR WSS LO
    • Measure the resistance between:
      (+) ABS Module Connector, Harness Side (-) Right Rear Wheel Speed Sensor Connector, Harness Side
      RR WSS HI RR WSS HI
      RR WSS LO RR WSS LO
    • Is the resistance less than 3 ohms? 
    Yes No
    Go to  B7. REPAIR the open circuit.
  7. B7: CHECK FOR RETURNING DTCS 
    • ABS Module connector connected.
    • Connect the suspect wheel speed sensor electrical connector.
    • Ignition ON, engine OFF.
    • Clear the ABS DTCs.
    • Test drive the vehicle under normal driving conditions above 20 km/h (12 mph).
    • Carry out the ABS self-test.
    • Is one or more of the DTCs shown in the DTC Fault Trigger Conditions table present? 
    Yes No
    Go to  B8. The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.
  8. B8: VERIFY ALL WIRING CONNECTIONS 
    • Ignition OFF.
    • ABS Module connector disconnected.
    • Disconnect the suspect wheel speed sensor electrical connector.
    • Using a good light source, inspect all disconnected electrical connectors for the following:
      • corrosion - install new connector or terminal and clean the module pins
      • damaged or bent pins - install new terminals or pins
      • pushed-out pins - install new pins as necessary
      • spread terminals - install new terminals as necessary
    • Are the connectors free of corrosion, damaged pins, bent pins, pushed-out pins and spread terminals? 
    Yes No
    INSTALL a new WSS.
    INSTALL a new wheel speed sensor. REFER to REMOVAL AND INSTALLATION    		 REPAIR the affected connectors or terminals. REFER to OEM CONNECTOR REPAIR PROCEDURES (EXCEPT ELECTRIC) for schematic and connector information.
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