Diagnostic Test

CHECK FOR AN ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, read ABS DTCs and record on the repair order.
3. With the scan tool, erase ABS DTCs.
  CAUTION:
  Make sure brake capability is available before road testing.
4. Road test the vehicle over 40 km/h (25 mph).
  NOTE:
  Vehicle must be driven above 40 km/h (25 mph) for two minutes before set conditions are met.
5. With the scan tool, read ABS DTCs.
  Did the DTC return?
  
  Yes
  - Go To 3
  No
  - Go To 2
CHECK WHEEL SPEED SENSOR SIGNALS
1. 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.
2. Slowly accelerate as straight as possible from a stop to 40 km/h (25 mph).
  Is the Left Front WSS speed showing 0 km/h (0 mph), not matching other wheels, or showing erratic behavior?
  
  Yes
  - Go To 3
  No
  - Perform ABS INTERMITTENT CONDITION diagnostic procedure. Refer to ABS INTERMITTENT CONDITION .
CHECK LEFT FRONT WSS 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. Remove the key from the Ignition Switch, close doors and allow the ABS Module to shut down.
  NOTE:
  Allow up to two minutes for the ABS Module to shut down. Opening the vehicle door will interrupt the shut down process.
2. Inspect the ABS Module harness connector and the Left Front WSS harness connector.
3. Check the Left Front WSS for looseness, excessive corrosion and not properly fastened.
4. Inspect the (B8) Left Front WSS Signal and (B9) Left Front WSS Supply circuits between the Left Front WSS and Anti-lock Brake System (ABS) Module for damage.
  Is the Left Front WSS 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 LEFT FRONT WHEEL SPEED SENSOR FOR DAMAGE
1. Remove the Left Front Wheel Speed Sensor.
2. Inspect the Wheel Speed Sensor for proper mounting.
3. Inspect the Wheel Speed Sensor harness and connector.
4. Inspect the Wheel Speed Sensor for excessive debris on the sensor.
  Is the Left Front Wheel Speed Sensor damaged?
  
  Yes
  - Replace the Left Front Wheel Speed Sensor in accordance with the Service Information. Refer to SENSOR, WHEEL SPEED, FRONT, REMOVAL .
  - Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  No
  - Go To 5
CHECK LEFT FRONT WHEEL BEARING AND HUB OR ENCODER FOR DAMAGE
1. Inspect the Left Front wheel bearing, hub and Encoder for excessive runout, clearance or damage.
  NOTE:
  Refer to the appropriate service information, if necessary, for procedures or specifications.
  
  Is the Left Front Wheel Bearing, Hub or Encoder Damaged?
  
  Yes
  - Replace the Hub and Wheel Bearing in accordance with the Service Information. Refer to HUB AND BEARING, REMOVAL .
  - Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  No
  - Go To 6
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 .
2. Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
3. Road test the vehicle over 40 km/h (25 mph).
  NOTE:
  Vehicle must be driven above 40 km/h (25 mph) for two minutes before set conditions are met.
4. With the scan tool, read ABS DTCs.
  Does the DTC remain active?
  
  Yes
  - Replace the Anti-lock Brake System (ABS) Module in accordance with the Service Information. Refer to MODULE, ANTI-LOCK BRAKE SYSTEM (ABS), REMOVAL .
  - Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
  No
  - Test Complete.