Code A021, Left Front Wheel Speed Is Zero: 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 EBCM to calculate a wheel speed of zero MPH. This code sets if 3 wheel speed sensors are rotating at least 5 MPH and one wheel speed sensor is zero MPH.

1. Determines if Code A032 is present.
2. Verifies if fault is currently present.
3. Identifies apparent physical damage that may cause code to set.
4. Checks if sensor internal resistance is correct.
5. Ensures sensor circuit has continuity.
6. Ensures sensor circuit is not internally shorted.
7. Checks for open in wheel speed signal high (+) circuit.
8. Checks for open in wheel speed signal low (-) circuit.
9. Ensures Code A021 is not caused by poor EBCM connections.