Primary oxygen sensor is the one closest the engine.


"Frank van Hoof" <thehoofies@sympatico.ca> wrote in message
news:Jgw2f.2724$S43.199833@news20.bellglobal.com.. .
>I have a check engine code P0135 in on my 98 Civic, which is supposed to be
> the primary oxygen sensor heater.
>
> Is this the oxygen sensor nearest to engine - just in the top of the
> exhaust
> manifold, or the one further down?
>
> Any comments on aftermarket Oxygen sensors?
>
> Frank
>
>