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Home >> Ford >> 2021 >> Explorer Limited Hybrid, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 497 (Abs Guided Routine) >> Pinpoint Tests >> Pinpoint Tests 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 2020 Ford Explorer. 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.
Fig 1: Anti-Lock Brake System-A (ABS-A) Module Connector - C135A
G13402635Courtesy of FORD MOTOR CO.

Harness Side

Circuit Pin
LR WSS LO (Left Rear Wheel Speed Sensor Low) - RCA18 9 (BROWN/GREEN)
LR WSS HI (Left Rear Wheel Speed Sensor High) - VCA04 8 (BLUE/ORANGE)
RR WSS LO (Right Rear Wheel Speed Sensor Low) - RCA20 5 (BROWN)
RR WSS HI (Right Rear Wheel Speed Sensor High) - VCA06 4 (WHITE/ORANGE)
Fig 2: Anti-Lock Brake System-B (ABS-B) Module Connector - C135B
G13402636Courtesy of FORD MOTOR CO.

Harness Side

Circuit Pin
Fig 3: Left Rear Wheel Speed Sensor Connector - C440
G13402637Courtesy of FORD MOTOR CO.

Harness Side

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 4: Right Rear Wheel Speed Sensor Connector - C426
G13402638Courtesy of FORD MOTOR CO.

Harness Side

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.
    • Put the ABS module in sleep mode by performing the following steps:
      • With ALL doors closed, set the ignition from ON to OFF.
      • Disconnect the diagnostic scan tool.
      • Open the door, exit the vehicle and close the door.
      • Wait a minimum of 90 seconds for the ABS module to enter sleep mode.
    • Ignition ON, engine OFF.

      Carry out the ABS self-test.

    • Are any of the DTCs shown in the 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), 14 (Circuit Short to Ground or Open Circuit) or 16 (Circuit Voltage Below Threshold), Go to  N3.      		 The system is operating correctly at this time. INSPECT both rear 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_A Module connector disconnected. (C135A)
    • ABS_B Module connector disconnected. (C135B)
    • 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_A Module connector disconnected. (C135A) If not previously disconnected.
    • ABS_B Module connector disconnected. (C135B) 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 100, 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 than 100, 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 (C440) Connector, Harness Side
      LR WSS LO LR WSS LO - RCA18 - Pin 2
      LR WSS HI LR WSS HI - VCA04 - Pin 1
    • Measure the resistance between:
      (+) ABS_A Module (C135A) Connector, Harness Side (-) Left Rear Wheel Speed Sensor (C440) Connector, Harness Side
      LR WSS LO - RCA18 (BROWN/GREEN) - Pin 9 LR WSS LO - RCA18 - Pin 2
      LR WSS HI - VCA04 (BLUE/ORANGE) - Pin 8 LR WSS HI - VCA04 - Pin 1
    • For the right rear wheel speed sensor:
    • Measure the resistance between:
      (+) ABS Module Connector, Harness Side (-) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side
      RR WSS LO RR WSS LO - RCA20 - Pin 2
      RR WSS HI RR WSS HI - VCA06 - Pin 1
    • Measure the resistance between:
      (+) ABS_A Module (C135A) Connector, Harness Side (-) Right Rear Wheel Speed Sensor (C426) Connector, Harness Side
      RR WSS LO - RCA20 (BROWN) - Pin 5 RR WSS LO - RCA20 - Pin 2
      RR WSS HI - VCA06 (WHITE/ORANGE) - Pin 4 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_A Module connector connected. (C135A) Make sure the connector seats and latches correctly.
    • ABS_B Module connector disconnected. (C135B)
    • 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 the Anti-Lock Brake System (ABS) and Stability Control article.      		 Go to  N7.
  7. N7: VERIFY ALL WIRING CONNECTIONS 
    • Ignition OFF.
    • ABS_A Module connector disconnected. (C135A) If not previously disconnected.
    • ABS_B Module connector disconnected. (C135B) If not previously 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 the Connector Repair Procedures wiring diagrams for schematic and connector information.
  8. N8: CHECK FOR APPLICABLE SERVICE ARTICLES 
    • Check OASIS for any service articles: TSB, GSB, SSM or FSA.
    • Do any applicable service articles exist? 
  9. N9: 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.
      INSTALL a new ABS module. REFER to the 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.
  10. N10: CHECK FOR CORRECT ABS OPERATION 
    • ABS_A Module connector connected. (C135A) Make sure the connector seats and latches correctly.
    • ABS_B Module connector connected. (C135B) 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 EBB assembly.
      The HCU and ABS module are a single assembly known as the EBB unit.
      INSTALL a new EBB unit (HCU and ABS module assembly). REFER to the Anti-Lock Brake System (ABS) and Stability Control article.
      ORDER a replacement EBB unit 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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