The wheel speed sensor coil emits an electromagnetic field. A toothed ring on the wheel passes by the wheel speed sensor and disrupts this electromagnetic field. The disruption in the field causes the wheel speed sensor to produce a sinusoidal (AC) voltage signal. The frequency and amplitude of the sinusoidal (AC) voltage signal are proportional to the speed of the wheel. The amplitude of the wheel speed signal is also directly related to the distance between the wheel speed sensor coil and the toothed ring. This distance is referred to as the air gap.

DTC C0227 is an Ignition Latched DTC, which indicates that the above actions remain true until the ignition is turned to OFF (even if the cause of the DTC is intermittent).

Any of the following conditions may cause an intermittent malfunction:

Thoroughly check any circuitry that is suspected of causing the intermittent complaint for the following conditions:

If the customer says that the ABS indicator lamp is on only during humid conditions such as rain, snow, or vehicle wash, then thoroughly inspect all wheel speed sensor circuits for signs of water intrusion. Use the following procedure:

1. Spray the suspected area with a 5% salt water solution (two teaspoons of salt to 12 oz. of water).
2. Drive the vehicle above 24 km/h (15 mph) for at least 30 seconds.

If the DTC returns, replace the suspected harness.

When inspecting a wheel speed sensor, inspect the sensor terminals and the harness connector for corrosion. If evidence of corrosion exists, then replace the wheel speed sensor. Refer to Front Wheel Speed Sensor Replacement .

The numbers below refer to the steps in the diagnostic table:

2. This step checks the EBCM 24-way connector for looseness, corrosion, etc.

3. This step measures the resistance of the EBCM 24-way connector terminals 11 and 23.

4. This step measures the resistance at the left front wheel speed sensor connector.

6. This step inspects the left front WSS and the tone wheel for physical damage or excessive clearance.