Code A028, Excessive Right Rear Wheel Speed Variation: Notes

Wheel speed sensors produce an AC voltage signal with a frequency proportional to wheel speed and wheel speed sensor position in relation to a toothed ring. This code detects opens or a low output condition which would cause intermittent wheel speed sensor operation and/or sudden change in wheel speed determined to be unreasonable.

1. Determines if Code A035 is present.
2. Verifies fault is currently present.
3. Identifies apparent physical damage that may cause code to set.
4. Ensures sensor internal resistance is correct.
5. Ensures sensor circuit has good continuity.
6. Determines if sensor circuit is internally shorted.
7. Checks for open in wheel speed signal low (-) circuit.
8. Checks for open in wheel speed signal high (+) circuit.
9. Ensures Code A028 is not caused by poor EBCM connections.