1994 Honda Civic Faulty speedometer, CEL for Oxygen Sensor

Hi trdarch,

Thank you for the donation.

The VSS and O2 sensors are on different circuits so are not related.

After replacement of the VSS, did the problem go away for a short while before coming back?

If the VSS is not at fault, you would need to check the wire harness. Some connection might be poor somewhere causing the speedometer to fail intermittently.

What was the exact trouble codes retrieved for the O2 sensor?

After replacing the VSS the first time, the problem did go away but returned. However, after the last replacement, the VSS issue did not go away.

The code I am pulling is a code 41- primary O2 sensor heater malfunction.

Thanks again.

What is the engine variant? 1.5 , 1.6 or 1.5 VX?

Was the VSS replaced new or used? Have you tested the VSS functions on the vehicle?

Would you be able to perform tests with a DVOM if the procedures are given to you?

i think it's a 1.6 vTECH engine.

Both the VSS I have used have been used. I would probably be able to preform some tests if given instructions.

Thanks again.

Used VSS might not be reliable and I would not rule out the possibility of a faulty unit. Here are the diagnostic procedures for the VSS and HO2S. Hope there are good if not let me know and I will send them in PDF format to your email.