C0654 indicates that the vehicle’s left front wheel speed sensor circuit is reporting a high voltage signal, which the engine control unit interprets as a fault. The fault is related to the sensor, its wiring or the associated power supply.
The sensor itself can develop internal faults that cause a high output voltage.
Corrosion, pinched cable or broken insulation can create a high‑voltage reading.
If the sensor’s power supply is too high, the sensor will over‑voltage.
A loose connector can introduce intermittent high‑voltage spikes.
In very uncommon cases the control module may misread a normal signal as high voltage.
In most real-world cases the PCM is not the cause; the sensor or wiring is more likely. A PCM replacement is rarely required for this code.
The issue may be in the wiring or power supply; check for open circuits, shorts, or incorrect voltage.
A severely damaged bearing can interfere with sensor operation, but the primary indicator would be a sensor fault, not the bearing itself.