Hey guys,

I got a 98 Civic LX, 4 door, auto trans, 135k miles. It's completely stock and I bought it about 18 months ago. The last time it was smogged was when I purchased it and it passed just fine.

Around summer or fall of last year, my car threw a CEL code. I had it read and it came out showing P0240 with the description something to the effect of "Catalytic converter running below efficiency threshold." I wasn't sure if it was just a random glitch so I had the mechanic just turn it off for me and it remained off for the next several months.

Then around the start of this year, it threw the same code again but this time I left the light on. The CEL remained on for about a week and then turned off by itself. It has since never come back on.

My registration is coming up and this time I need to get it smogged again. I'm worried that my cats might be bad, but i'm also wondering if maybe the P0240 code was just a false alert perhaps my sensors were dirty for a moment and then cleaned up by some extended freeway driving.

I know failing smog aint the end of the world but I would rather fix the issue beforehand and not have a failed smog check on the record if I knew I would 100% fail smog.

My question is whether there is a decent chance I can still pass smog or is a previous P0240 code a guaranteed dedication that my cats are bad?

If it matters, I am in CA and I haven't noticed any colored smoke or bad smelling fumes from the exhaust.


Thanks!

 

I had a p0420 code on my 98 lx but they don't check emissions where I live so I just used an 02 sensor spacer to get rid of the cel, but if you can't tell a difference in performance at all I'd say its fine but I know cali is super strict on emissions so idk lol our inspection is $14.50

 

Thanks. Well the CEL hasn't come back on for a while now and I don't expect it to. It drives fine and everything but i'm just worried about the actual smog test. Can anyone else chime in?