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Visual Inspection and Diagnostic Pre-checks

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NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.
Fig 1: Antilock Braking System Module Connector (C135)
GFDW79032Courtesy of FORD MOTOR COMPANY
CIRCUIT AND PIN DESCRIPTION

Circuit Pin
LR WSS LO (Left Rear Wheel Speed Sensor Low) - RCA18 6 (BROWN/GREEN)
LR WSS HI (Left Rear Wheel Speed Sensor High) - VCA04 7 (BLUE/ORANGE)
RR WSS LO (Right Rear Wheel Speed Sensor Low) - RCA20 10 (BROWN)
RR WSS HI (Right Rear Wheel Speed Sensor High) - VCA06 11 (WHITE/ORANGE)
Fig 2: Left Rear Wheel Speed Sensor Connector (C440)
G12970716Courtesy of FORD MOTOR CO.
CIRCUIT AND PIN DESCRIPTION

Circuit Pin
LR WSS LO (Left Rear Wheel Speed Sensor Low) - RCA18 2 (BROWN/GREEN)
LR WSS HI (Left Rear Wheel Speed Sensor High) - VCA04 1 (BLUE/ORANGE)
Fig 3: Right Rear Wheel Speed Sensor Connector (C426)
G12970717Courtesy of FORD MOTOR CO.
CIRCUIT AND PIN DESCRIPTION

Circuit Pin
RR WSS LO (Right Rear Wheel Speed Sensor Low) - RCA20 2 (BROWN)
RR WSS HI (Right Rear Wheel Speed Sensor High) - VCA06 1 (WHITE/ORANGE)
  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. (C135)
    • 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 (C440) Connector, Harness
      Side      		 (-)
      LR WSS LO - RCA18 (BROWN/GREEN) - Pin 2 Ground
      LR WSS HI - VCA04 (BLUE/ORANGE) - Pin 1 Ground
    • For the right rear wheel speed sensor:
    • Measure the voltage between:
      (+) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side (-)
      RR WSS LO - RCA20 (BROWN) - Pin 2 Ground
      RR WSS HI - VCA06 (WHITE/ORANGE) - Pin 1 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. (C135) (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 (C440) Connector, Harness
      Side      		 (-)
      LR WSS LO - RCA18 (BROWN/GREEN) - Pin 2 Ground
      LR WSS HI - VCA04 (BLUE/ORANGE) - Pin 1 Ground
    • For the right rear wheel speed sensor:
    • Measure the resistance between:
      (+) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side (-)
      RR WSS LO - RCA20 (BROWN) - Pin 2 Ground
      RR WSS HI - VCA06 (WHITE/ORANGE) - Pin 1 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 (C440) Connector, Harness Side (-) Left Rear Wheel Speed Sensor (C440) Connector, Harness Side
      LR WSS HI - VCA04 (BLUE/ORANGE) - Pin 1 LR WSS LO - RCA18 - Pin 2
    • For the right rear wheel speed sensor:
    • Measure the resistance between:
      (+) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side (-) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side
      RR WSS HI - VCA06 (WHITE/ORANGE) - Pin 1 RR WSS LO - RCA20 - Pin 2
    • 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 (C135) Connector, Harness Side (-) Left Rear Wheel Speed Sensor (C440) Connector, Harness Side
      LR WSS LO - RCA18 (BROWN/GREEN) - Pin 6 LR WSS LO - RCA18 - Pin 2
      LR WSS HI - VCA04 (BLUE/ORANGE) - Pin 7 LR WSS HI - VCA04 - Pin 1
    • For the right rear wheel speed sensor:
    • Measure the resistance between:
      (+) ABS Module (C135) Connector, Harness Side (-) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side
      RR WSS LO - RCA20 (BROWN) - Pin 10 RR WSS LO - RCA20 - Pin 2
      RR WSS HI - VCA06 (WHITE/ORANGE) - Pin 11 RR WSS HI - VCA06 - Pin 1
    • 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. (C135)
    • Ignition ON, engine OFF.
    • For the left rear wheel speed sensor:
    • Measure the voltage between:
      (+) Left Rear Wheel Speed Sensor (C440) Connector, Harness Side (-) Left Rear Wheel Speed Sensor (C440) Connector, Harness Side
      LR WSS HI - VCA04 (BLUE/ORANGE) - Pin 1 LR WSS LO - RCA18 - Pin 2
    • For the right rear wheel speed sensor:
    • Measure the voltage between:
      (+) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side (-) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side
      RR WSS HI - VCA06 (WHITE/ORANGE) - Pin 1 RR WSS LO - RCA20 - Pin 2
    • Is the voltage greater 10 volts? 
      Yes No
      INSTALL a new WSS.
      REFER to Anti-Lock Brake System (ABS) and Stability Control article      		 Go to  N7.
  7. N7: VERIFY ALL WIRING CONNECTIONS 
    • Ignition OFF.
    • ABS Module connector disconnected. (C135)
    • 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 Connector Repair Procedures article for schematic and connector information.
  8. N8: CHECK FOR CORRECT ABS MODULE OPERATION 
    • ABS Module connector connected. (C135) 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) and Stability Control article
      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.
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