DTC 25 - Left Front Excessive Wheel Speed Variation: Notes

NOTE: For circuit and connector terminal identification, see WIRING DIAGRAMS .

As a toothed ring passes the wheel speed sensor, changes in electromagnetic field causes sensor to produce an AC voltage signal. Frequency of signal is proportional to wheel speed. Magnitude of signal is directly related to wheel speed and the proximity of the wheel speed sensor to the toothed ring. This distance is also referred to as "air gap"

NOTE: Test numbers refer to test numbers on diagnostic chart.

Verifies malfunction is currently present.
Checks to see if excessive wheel bearing play caused DTC.
Identifies visibly damaged wheel speed sensor or circuit.
Checks wheel speed sensor for proper resistance (at room temperature).
Ensures wheel speed sensor and sensor ring generate proper voltage.
Ensures wheel speed sensor is not shorted to ground.
Checks for proper voltages at speed sensor harness connector.
Ensures wheel speed sensor circuit is not internally shorted.
Checks for open in Blue wire.
Checks for open in Blue/Black wire.
Checks for short to ground in both wheel speed signal circuits.
Ensures DTC was not set due to a poor connection.