C1014 Left Front Wheel Speed Comparative Performance

C1014 Left Front Wheel Speed Comparative Performance - When the Left Front Wheel Speed Sensor (WSS) reading is different from the readings received from the other sensor at a vehicle speed above 40 km/h (25 mph).

The Antilock Brake System (ABS) Module compares WSS reading from side to side on an axle and front to rear.

Possible Causes

• Left front WSS loose circuits/connector/terminal damage.
• Improper Left Front tire pressure/mismatched tires.
• Left Front tone wheel/bearing damage.
• Left Front Wheel Speed Sensor (WSS).
• Antilock Brake System (ABS) Module.

Diagnose C1014 Left Front Wheel Speed Comparative Performance

Step 1. Check for DTC

This DTC must be active for the results of this test to be valid. Turn the ignition on, with the scan tool, record and erase DTC. Make sure braking capability is available before road  testing. Road test the vehicle over 40 km/h (25 mph). Vehicle must be driven above 40 km/h (25 mph) for set conditions to be met. With the scan  tool, read DTC.

Does the scan tool display C1014 Left Front Wheel Speed Comparative Performance ?

YES, go to step 3.

NO, go to step 2.

Step 2. Check wheel speed sensor signals

Turn the ignition on, with the scan tool, monitor and graph all the WSS speeds and compare graph while an assistant drives the vehicle. If graph shows periodic dropouts pay close attention to the tone wheel. 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 step 3.

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.

Step 3. Check for improper left front tire pressure/mismatched tires
Turn the ignition off, check and adjust the Left Front tire pressure, check and adjust all other tire pressure. Inspect for mismatched tires in vehicle.

Is the Left Front tire improperly inflated or mismatched tires on vehicle ?

YES, repair as necessary.
NO, go to step 4.

Step 4. Check Left Front WSS looseness, inspect circuit/terminal for damage
Check all terminals for broken, bent, pushed out, or corroded terminals.
Inspect the Antilock Brake System (ABS) Module harness connector, left front WSS, and left front WSS harness connector. Inspect the left front WSS for looseness, excessive corrosion and not properly fastened. Inspect the left Front WSS signal and left Front WSS supply circuits between the left Front WSS and Antilock Brake System (ABS) Module for damage.

Is the Left Front WSS loose or any of the wiring/connector/terminals damaged ?

YES, repair as necessary.
NO, go to step 5.

Step 5. Check Left Front wheel speed sensor for damage
Remove the Left Front wheel speed sensor, inspect the Left Front Wheel speed sensor face for damage.

Is the Left Front Wheel speed sensor damage ?

YES, replace sensor and hub assembly.
NO, go to step 6.

Step 6. Check Left Front tone wheel/bearing for damage
Inspect the Left Front tone wheel/Bearing for damage, missing teeth, cracks, corrosion or looseness. The tone wheel teeth should be perfectly square, not bent, or nicked.

Is the Left Front tone wheel/Bearing damaged ?

YES, repair as necessary.
NO, go to step 7.

Step 7. Left Front wheel speed sensor
Replace the Left front wheel speed sensor, road test the vehicle over 40 km/h (25 mph). Vehicle must be driven above 40 km/h (25 mph) for set conditions to be met.
With the scan tool, read ABS DTC.

Did DTC C1014 Left Front Wheel Speed Comparative Performance reset ?

YES, replace the Antilock Brake System (ABS) Module. Perform the ABS Verification Test.
NO, test complete for DTC C1014 Left Front Wheel Speed Comparative Performance.

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