My 2000 Neon SOHC Highline has a perpetual check engine code 0456. It's been well over a year. I'll clear it and within a few hundred miles it's back.

I know this code, (minor emissions leak or something) is usually due to the gascap not being clicked tight. I always make sure mine is closed properly, so I recently bought a new Mopar gascap and the problem is still there.

What else could this code be from?

I mentioned in a previous thread my car feels like it needs a tuneup. I was thinking the o2 sesors, wiring harness, plugs or timing belt, but these all have codes of their own, no?



It has 126k miles, and the only engine mod is a K&N filter (and R/T exhaust).

Any thoughts?

TIA.

 

Any leak any where in the evap system can set this code and there is no easy way to locate it. It could be anything from a split hose to a fuel tank. The last neon I fixed with this code was a purge solenoid, but it would probably be cheaper to let a dealer fix it rather than to guess.