DTC A025 - Left Front Excessive Wheel Speed Variation: Notes

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"

1. Verifies malfunction is currently present.
2. Checks to see if excessive wheel bearing play caused DTC.
3. Identifies visibly damaged wheel speed sensor or circuitry.
4. Checks wheel speed sensor for proper resistance (at room temperature).
5. Ensures wheel speed sensor and sensor ring generate proper voltage.
6. Ensures wheel speed sensor is not shorted to ground. Tester J 39200 is a DVOM with a 10-megohm input impedance.
7. Checks for proper voltages at speed sensor harness connector.
8. Ensures wheel speed sensor circuitry is not internally shorted.
9. Checks for open in circuit No. 873.
10. Checks for open in circuit No. 830.
11. Checks for short to ground in both wheel speed signal circuits.
12. Ensures DTC was not set due to a poor connection between EBCM connector and EBCM.