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Home >> Alfa Romeo >> 2021 >> Stelvio Ti >> Repair and Diagnosis >> Brakes >> Anti-Lock Brakes >> Anti-Lock Brakes (Abs) - DTCS C0010-01 To C104A-29 >> DTC Troubleshooting >> C0031-01-Speed Sensor Front Left - General Electrical Failure >> Diagnostic Test

Diagnostic Test

  1. CHECK FOR AN ACTIVE DTC 
    1. Perform any Service Bulletins that may apply.
    2. Turn the ignition on.
    3. With the scan tool, read ABS DTCs and record on the repair order.
    4. With the scan tool, read and record Environmental Data to help identify the conditions in which the DTC was set.
    5. With the scan tool, erase ABS DTCs.
    6. Cycle the ignition switch from off to on.
    7. With the scan tool, read ABS DTCs.

      Did the DTC return?

      Yes 

      • Go To  2

      No 

      • The condition that caused the symptom is currently not present. Inspect the related wiring for a possible intermittent condition. Look for any chafed, pierced, pinched, or partially broken wires.
      • Perform the ABS INTERMITTENT CONDITION TEST. Refer to ABS INTERMITTENT CONDITION .
  2. CHECK CONNECTOR/TERMINAL FOR DAMAGE 
    NOTE:

    Check all terminals for broken, bent, pushed out, or corroded terminals.

    1. Turn the ignition off.
    2. Inspect the Wheel Speed Sensor harness and connector.
    3. Inspect the Wheel Speed Sensor for excessive debris on the sensor.

      Were any problems found?

      Yes 

      • Repair as necessary in accordance with the Service Information.
      • Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

      No 

      • Go To  3
  3. CHECK (B9) LEFT FRONT WHEEL SPEED SENSOR SUPPLY CIRCUIT VOLTAGE 
    1. Disconnect the Left Front Wheel Speed Sensor harness connector.
    2. Turn the ignition on.
    3. Measure the voltage between the (B9) Left Front Wheel Speed Sensor Supply circuit and ground.

      Is the voltage above 10 volts?

      Yes 

      • Go To  6

      No 

      • Go To  4
  4. (B9) LEFT FRONT WHEEL SPEED SENSOR SUPPLY CIRCUIT SHORTED TO GROUND 
    1. Turn the ignition off.
    2. Disconnect the ABS Module harness connector.
    3. Measure the resistance between the (B9) Left Front Wheel Speed Sensor Supply circuit and ground.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Repair the (B9) Left Front Wheel Speed Sensor Supply circuit for a short to ground.
      • Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

      No 

      • Go To  5
  5. (B9) LEFT FRONT WHEEL SPEED SENSOR SUPPLY CIRCUIT OPEN 
    1. Measure the resistance of the (B9) Left Front Wheel Speed Sensor Supply circuit between the Left Front Wheel Speed Sensor harness connector and the ABS Module harness connector.

      Is the resistance below 5 Ohms?

      Yes 

      • Go To  6

      No 

      • Repair the open (B9) Left Front Wheel Speed Sensor Supply circuit.
      • Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  6. (B8) LEFT FRONT WHEEL SPEED SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE 
    1. Turn the ignition on.
    2. Measure the voltage of the (B8) Left Front Wheel Speed Sensor Signal circuit at the Left Front Wheel Speed Sensor harness connector.

      Is there any voltage present?

      Yes 

      • Repair the (B8) Left Front Wheel Speed Sensor Signal circuit for a short to voltage.
      • Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

      No 

      • Go To  7
  7. (B8) LEFT FRONT WHEEL SPEED SENSOR SIGNAL CIRCUIT SHORTED TO GROUND 
    1. Turn the ignition off.
    2. Measure the resistance between the (B8) Left Front Wheel Speed Sensor Signal circuit and ground.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Repair the (B8) Left Front Wheel Speed Sensor Signal circuit for a short to ground.
      • Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

      No 

      • Go To  8
  8. (B8) LEFT FRONT WHEEL SPEED SENSOR SIGNAL CIRCUIT OPEN 
    1. Measure the resistance of the (B8) Left Front Wheel Speed Sensor Signal circuit between the Left Front Wheel Speed Sensor harness connector and the ABS Module harness connector.

      Is the resistance below 5 Ohms?

      Yes 

      • Go To  9

      No 

      • Repair the open (B8) Left Front Wheel Speed Sensor Signal circuit.
      • Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  9. (B9) LEFT FRONT WHEEL SPEED SENSOR SUPPLY CIRCUIT SHORTED TO THE (B8) LEFT FRONT WHEEL SPEED SENSOR SIGNAL CIRCUIT 
    1. Turn the ignition off.
    2. Measure the resistance between the (B9) Left Front Wheel Speed Sensor Supply circuit and the (B8) Left Front Wheel Speed Sensor Signal circuit at the ABS Module harness connector.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Repair (B9) Left Front Wheel Speed Sensor Supply circuit for a short to the (B8) Left Front Wheel Speed Sensor Signal circuit.
      • Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .

      No 

      • Go To  10
  10. LEFT FRONT WHEEL SPEED SENSOR 
    1. Replace the Left Front Wheel Speed Sensor in accordance with the Service Information. Refer to SENSOR, WHEEL SPEED, FRONT, REMOVAL AND INSTALLATION .
    2. Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
      WARNING:

      To avoid possible serious or fatal injury, check brake capability is available before road testing.

    3. Road test the vehicle over 40 km/h (25 mph).
      NOTE:

      Vehicle must be driven for several minutes above 40 km/h (25 mph) for set conditions to be meet.

    4. With the scan tool, read ABS DTCs.

      Does the DTC remain active?

      Yes 

      • Go To  11

      No 

      • Test complete.
  11. CHECK RELATED HARNESS CONNECTIONS 
    1. Disconnect the ABS Module harness connector.
    2. Disconnect all related in-line harness connections (if equipped).
    3. Disconnect the related component harness connectors.
    4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Perform a terminal drag test on each connector terminal to verify proper terminal tension.

      Repair any conditions that are found.

    5. Connect the ABS Module harness connector. Be certain that the harness connector is fully seated and the connector lock is fully engaged.
    6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. Connect the related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. With the scan tool, erase DTCs.
      WARNING:

      To avoid possible serious or fatal injury, check brake capability is available before road testing.

    9. Using the recorded Event and Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
    10. With the scan tool, read ABS Module DTCs.

      Did the DTC return?

      Yes 

      No 

      • The wiring or poor connection problem has been repaired.
      • Perform ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
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