C1041-LEFT FRONT TONE WHEEL PERFORMANCE

For a complete wiring diagram, refer to the Wiring Information.

When Monitored:
With the ignition on.
Set Condition:
When the Anti-Lock Brake Module detects periodic drops of a Wheel Speed Sensor (WSS) signal.

Possible Causes
LEFT FRONT TONE WHEEL/BEARING DAMAGE
IMPROPER LEFT FRONT TIRE PRESSURE/MISMATCHED TIRES
DIRT, METAL, DAMAGED TONE WHEEL/SENSOR

1. 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

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

3. 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

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

Replace the Left Front Tone Wheel/Bearing in accordance with the Service Information.
Perform ABS VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Antilock Brake (ABS) - Standard Procedure).