My two cents:

I wouldn't say you got ripped off just yet. That site is very unusual. The
dealer would have charged you closer to what www.slhonda.com would ask
(around $150-$200 for each oxygen sensor, not counting the labor), and
probably more.

The primary oxygen sensor (upstream of the cat converter) is fairly critical
to the car's operation, supplying a signal to the engine computer that
ultimately adjusts the fuel-air ratio for different operating conditions. If
the primary one died, then it should be replaced sooner rather than later.

The secondary oxygen sensor (downstream of the cat converter) is mostly
there to monitor the cat converter.

I would ask the guy whether he put in genuine Honda sensors or aftermarket
ones, for your records. Aftermarket ones tend not to last as long, from my
reading.

As far as asking for a refund: There's no harm in doing so, but a person has
to know what oxygen sensors do to argue the case. You could say reports on
the internet are that usually only one fails at a time. Then you could ask
him, "So which one really failed"? Then add you're going to be left feeling
you got ripped off unless he remedies the situation or proves both really
went bad.

I'm sure the guy will roll his eyes when he hears this. And he'd be partly
justified: After all, you agreed to the work. But he wouldn't be fully
justified, because it would seem he wasn't fully honest with you. On the
third hand, you're still asking questions /after/ the fact. That doesn't
seem completely fair. Furthermore, I don't think it will be easy to get
evidence the guy was lying before (assuming he was). Ideally the tech will
prove a certain code was set by the engine computer, but this long after the
fact?

If you do ask the guy for a refund, I wouldn't plan on using his shop in the
future.

I wouldn't expect any refund. Assuming only one sensor went bad, let him
know you won't be using him again and can't recommend his shop to others.
Then let him make up his mind. If he doesn't refund a cent, take it as a
lesson learned. We all suffer through such lessons with our cars but are
usually savvier the next time around. So it wasn't a total loss.

I'd also try to find out if the oxygen sensors would be covered under the
federal emissions warranty. Google on this for info. I have always found it
hard to nail down in specific situations. Dealer service departments are
usually pretty savvy on the subject.

Check back for another day or so to get others' opinions.

> wrote
> so I guess I got ripped off. He charged me $112 and $116 for two
> sensors and they sell on that site for around $62. I don't even know if
> he gave me Honda sensors. Can I go back to him and ask for a refund? I
> already paid him. My car is a 2000 Honda Civic LX Automatic 4 cyl. 77k
> miles. What led to the decision was that my service engine light was on
> and he plugged in that machine under my dashboard and it said the O2
> sensor malfunctioned.