I had a check engine light on in my '05 and the code the dealer pulled indicated catalytic converter.
However, I realized that the 75k tuneup had never been done, so I changed the spark plugs and, voila, no check engine light - for two weeks. then there it is again.
So, I hook it up OBD11 style and get: "P0420"-cat system effieciency below threshold Block 1
"C0001"-fuel volume regulator control, circuit open
"P120B"-undefined
"C3400"-undefined
Then, I get under the hood, and whatdayaknow- I forgot to tighten one of the clamps on the hose between the manifold and the air filter housing. Once I did that and cleared the codes the "check engine" light went bye-bye...
Of course, I realize I have to get the car out driving - which I've done - and let it build the codes (if any), so my question is : could that have contributed to all of those codes?
Thank you