Diagnostic Test

CHECK FOR A DIAGNOSTIC TROUBLE CODE (DTC) C1041-LEFT FRONT TONE WHEEL PERFORMANCE
NOTE:
This DTC must be active for the results of this test to be valid.
1. Turn the ignition on.
2. Using the scan tool, read DTCs.
3. Record DTC and Freeze Frame information.
4. Using the scan tool, erase DTCs.
5. Cycle the ignition switch off then on.
  CAUTION:
  Make sure braking capability is available before road testing.
6. Test drive the vehicle in a straight line to 40 km/h (25 mph).
  NOTE:
  Vehicle must be driven above 40 km/h (25 mph) for set conditions to be met.
7. Using the scan tool, read DTCs.
  Does the scan tool display: C1041-LEFT FRONT TONE WHEEL PERFORMANCE active?
  
  Yes
  - Go To 3
  No
  - Go To 2
CHECK WHEEL SPEED SENSOR SIGNALS
1. Turn the ignition on.
2. Using 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).
  Is the Left Front WSS speed showing 0 km/h (0 mph) or not matching other wheels or showing erratic behavior?
  
  Yes
  - Go To 3
  No
  - Perform ABS VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK FOR IMPROPER LEFT FRONT TIRE PRESSURE/MISMATCHED TIRES
1. Turn the ignition off.
2. Check and adjust the Left Front Tire pressure.
3. Check and adjust all other tire pressures.
4. Inspect for mismatched tires on vehicle.
  Is the Left Front Tire improperly inflated or mismatched tires on vehicle?
  
  Yes
  - Repair as necessary.
  - Perform ABS VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 4
CHECK THE LEFT FRONT TONE WHEEL/BEARING FOR DAMAGE
NOTE:
Check the tone wheel teeth for missing teeth, cracks, or looseness. Teeth should be perfectly square, not bent, or nicked.
1. Check the Left Front Tone Wheel/Bearing for damage.
2. Check the Left Front Tone Wheel for dirt.
  Was the tone wheel dirty?
  
  Yes
  - Clean tone wheel and sensor. Clear codes and retest.
  - Perform ABS VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Replace the Left Front Tone Wheel/Bearing in accordance with the Service Information.
  - Perform ABS VERIFICATION TEST. Refer to STANDARD PROCEDURE .