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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 N: Rear Wheel Speed Sensor Electrical Faults >> Visual Inspection and Diagnostic Pre-checks

Visual Inspection and Diagnostic Pre-checks

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.
CAUTION: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.
  1. N1: CHECK FOR FAULT REPEATABILITY 
    • Ignition ON, engine OFF.
    • Clear the ABS DTCs.
    • Ignition OFF.
    • Ignition ON, engine OFF.
    • Test drive the vehicle above 20 km/h (12 mph).
    • Carry out the ABS self-test.
    • Is one or more of the DTCs shown in the ABS DTC Fault Trigger Conditions table present? 
    Yes No
    For failure type byte 01 (General Electrical Failure), 12 (Circuit Short to Ground) or 15 (Circuit Short to Battery or Open Circuit), Go to  N2.
    For failure type byte 11 (Circuit Short to Ground) or 14 (Circuit Short to Ground or Open Circuit), Go to  N3.    		 The system is operating correctly at this time.
    INSPECT both front wheel speed sensor electrical connectors and the ABS module electrical connector.
    REPAIR or CLEAN the connector as necessary.
    ADDRESS the root cause of any connector or pin issues.
  2. N2: CHECK THE WHEEL SPEED SENSOR CIRCUITS FOR A SHORT TO BATTERY VOLTAGE 
    • Ignition OFF.
    • ABS Module connector disconnected.
    • Disconnect the suspect wheel speed sensor.
    • Ignition ON, engine OFF.
    • For the left rear wheel speed sensor:
    • Measure the voltage between:
      (+) Left Rear Wheel Speed Sensor Connector, Harness Side (-)
      LR WSS LO Ground
      LR WSS HI Ground
    • For the right rear wheel speed sensor:
    • Measure the voltage between:
      (+) Right Rear Wheel Speed Sensor Connector, Harness Side (-)
      RR WSS LO Ground
      RR WSS HI Ground
    • Is any voltage present? 
    Yes No
    REPAIR the circuit. Go to  N3.
  3. N3: CHECK THE WHEEL SPEED SENSOR CIRCUITS FOR A SHORT TO GROUND 
    • Ignition OFF.
    • ABS Module connector disconnected. (if not previously disconnected)
    • Disconnect the suspect wheel speed sensor (if not previously disconnected).
    • For the left rear wheel speed sensor:
    • Measure the resistance between:
      (+) Left Rear Wheel Speed Sensor Connector, Harness Side (-)
      LR WSS LO Ground
      LR WSS HI Ground
    • For the right rear wheel speed sensor:
    • Measure the resistance between:
      (+) Right Rear Wheel Speed Sensor Connector, Harness Side (-)
      RR WSS LO Ground
      RR WSS HI Ground
    • Are the resistances greater than 10, 000 ohms? 
    Yes No
    Go to  N4. REPAIR the circuit.
  4. N4: CHECK FOR SHORTED WHEEL SPEED SENSOR CIRCUITS 
    • For the left rear wheel speed sensor:
    • Measure the resistance between:
      (+) Left Rear Wheel Speed Sensor Connector, Harness Side (-) Left Rear Wheel Speed Sensor Connector, Harness Side
      LR WSS HI LR WSS LO
    • For the right rear wheel speed sensor:
    • Measure the resistance between:
      (+) Right Rear Wheel Speed Sensor Connector, Harness Side (-) Right Rear Wheel Speed Sensor Connector, Harness Side
      RR WSS HI RR WSS LO
    • Is the resistance greater 10, 000 ohms? 
    Yes No
    Go to  N5. REPAIR the circuit.
  5. N5: CHECK THE WHEEL SPEED CIRCUITS FOR AN OPEN 
    • For the left rear wheel speed sensor:
    • Measure the resistance between:
      (+) ABS Module Connector, Harness Side (-) Left Rear Wheel Speed Sensor Connector, Harness Side
      LR WSS LO LR WSS LO
      LR WSS HI LR WSS HI
    • For the right rear wheel speed sensor:
    • Measure the resistance between:
      (+) ABS Module Connector, Harness Side (-) Right Rear Wheel Speed Sensor Connector, Harness Side
      RR WSS LO RR WSS LO
      RR WSS HI RR WSS HI
    • Are the resistances less than 3 ohms? 
    Yes No
    Go to  N6. REPAIR the circuit.
  6. N6: CHECK THE ABS MODULE OUTPUT 
    • ABS Module connector connected.
    • Ignition ON, engine OFF.
    • For the left rear wheel speed sensor:
    • Measure the voltage between:
      (+) Left Rear Wheel Speed Sensor Connector, Harness Side (-) Left Rear Wheel Speed Sensor Connector, Harness Side
      LR WSS HI LR WSS LO
    • For the right rear wheel speed sensor:
    • Measure the voltage between:
      (+) Right Rear Wheel Speed Sensor Connector, Harness Side (-) Right Rear Wheel Speed Sensor Connector, Harness Side
      RR WSS HI RR WSS LO
    • Is the voltage greater 10 volts? 
    Yes No
    INSTALL a new WSS.
    REFER to REMOVAL AND INSTALLATION    		 Go to  N7.
  7. N7: VERIFY ALL WIRING CONNECTIONS 
    • Ignition OFF.
    • ABS Module connector disconnected.
    • 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
    Go to  N8. REPAIR the affected connectors or terminals. Refer to OEM CONNECTOR REPAIR PROCEDURES (EXCEPT ELECTRIC) for schematic and connector information.
  8. N8: CHECK FOR CORRECT ABS MODULE OPERATION 
    • ABS Module connector connected. Make sure the connector seats and latches correctly.
    • Connect the suspect wheel speed sensor electrical connector. Make sure the connector seats and latches correctly.
    • Operate the system and determine if the concern is still present.
    • Is the concern still present? 
    Yes No
    INSTALL a new ABS module.
    CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA.
    If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions.
    If no service articles address this concern, INSTALL a new ABS module. REFER to ANTI-LOCK BRAKE SYSTEM (ABS) MODULE
    ORDER a replacement ABS module and INCLUDE the RVC on the form.
    If this is a Ford paid repair, INCLUDE the RVC on the warranty claim form.    		 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.
    If this is a Ford paid repair, INCLUDE the RVC on the warranty claim form.
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