Circuit Description

Speed sensor at each wheel produces an A/C signal to ABS ECU as 48-tooth rotor passes permanent magnet sensor. Frequency of A/C signal changes with wheel speed. DTC is set under the following conditions:

• No speed sensor pulses are input to ECU for 5 seconds with vehicle speed 6 MPH or greater.
• Momentary interruption of speed sensor signal occurs at least 7 times during cycle of ignition switch.
• Abnormal speed sensor signal fluctuation with vehicle speed of 12 MPH or greater.

Possible causes are:

• Speed sensor.
• Speed sensor open or short circuit.
• ECU.