Diagnostic Test

WARNING: This page is about a different car, the 2015 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.

VERIFY THE DTC IS ACTIVE
1. Turn the ignition on.
2. With the scan tool, record and erase DTCs.
  CAUTION:
  Make sure braking capability is available before road testing.
3. Road test the vehicle over 40 km/h (25 mph).
  NOTE:
  Vehicle must be driven above 40 km/h (25 mph) for set conditions to be met.
4. With the scan tool, read DTCs.
  Is the DTC active at this time?
  
  Yes
  - Go To 2
  No
  - Perform the ABS-INTERMITTENT CONDITION TEST. Refer to ABS INTERMITTENT CONDITION .
CHECK THE WHEEL SPEED SENSOR SIGNALS
1. Turn the ignition on.
2. With the scan tool, monitor and graph ALL the WSS speeds and compare graph while an assistant drives the vehicle.
  NOTE:
  If graph shows periodic dropouts pay close attention to the tone wheel.
3. Slowly accelerate as straight as possible from a stop to 40 km/h (25 mph).
  Are the Wheel Speed Sensors speed showing 0 km/h (0 mph), not matching other wheels, or showing erratic behavior?
  
  Yes
  - Go To 3
  No
  - Perform the ABS INTERMITTENT CONDITION diagnostic procedure. Refer to ABS INTERMITTENT CONDITION .
CHECK THE FOR LOOSENESS, INSPECT CIRCUITS/CONNECTORS/TERMINALS FOR DAMAGE
NOTE:
Check all terminals for broken, bent, pushed out, or corroded terminals.
1. Turn the ignition off to the lock position.
2. Inspect the ABS Module harness connector and the Wheel Speed Sensor harness connectors.
3. Check the Wheel Speed Sensors for looseness, excessive corrosion and not properly fastened.
4. Inspect the Wheel Speed Sensor circuits between the Wheel Speed Sensor and ABS Module for damage.
  Are the Wheel Speed Sensors loose or any of the wiring/connectors/terminals damaged?
  
  Yes
  - Repair as necessary.
  - Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  No
  - Go To 4
CHECK CORRECT WHEEL SPEED SENSORS INSTALLED
1. Inspect the Wheel Speed Sensor for proper mounting.
2. Remove the Wheel Speed Sensors in accordance with the Service Information.
3. Inspect the Wheel Speed Sensors for excessive debris on the sensor.
4. Inspect the Wheel Speed Sensor for proper mounting.
5. Verify the correct Wheel Speed Sensor were installed.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  No
  - Go To 5
ANTI-LOCK BRAKE SYSTEM (ABS) MODULE
1. Replace the Anti-lock Brake System (ABS) Module in accordance with the Service Information. Refer to MODULE, ANTI-LOCK BRAKE SYSTEM, REMOVAL .
2. Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  CAUTION:
  Make sure braking capability is available before road testing.
3. Road test the vehicle over 40 km/h (25 mph).
  NOTE:
  Vehicle must be driven above 40 km/h (25 mph) for set conditions to be meet.
4. With the scan tool, read ABS DTCs.
  Does the remain active at this DTC?
  
  Yes
  - Replace the Wheel Speed Sensors in accordance with the Service Information. Refer to SENSOR, WHEEL SPEED, FRONT, REMOVAL .
  - Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  No
  - Test complete.