Possible causes

– Faulty Vehicle Speed Sensor
– Vehicle speed sensor harness or connectors is open or shorted
– Vehicle speed sensor circuit poor electrical connection
– Faulty Engine Control Module (ECM)

Tech notes

P0501 1998 Honda Civic Speed Sensor Diagnosis

User Submitted Video

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Speedometer may not work properly
– Transmission shifting problem

P0501 HONDA Description

The vehicle speed sensor outputs a 4 pulse signal for every revolution of the rotor shaft, which is rotated by the transmission output shaft via the driven gear. After this signal is converted into a more precise rectangular waveform by the waveform shaping circuit inside the combination meter, it is then transmitted to the Engine Control Module (ECM). The ECM determines the vehicle speed based on the frequency of these pulse signals.

HONDA Technical Service Bulletins for P0501 code