Contour Enthusiasts Group Archives Forums General Troubleshooting While they're replacing my cats...

Next Wednesday I am having my cats replaced pursuant to a P0420 CEL that happened to me last week. For the record, my car has 63,5xx miles at the moment.

When I spoke to the service advisor to set up the appointment, I asked if replacing the O2 sensors was covered under this warranty repair. He said he wasn't sure, and that he would get back to me.

My question is this: if they're going to be mucking around in that neighbourhood anyway, I should probably have them replace the four (there are four of them, right?) O2 sensors while they're down there, right? (Even if I have to shell out the money out-of-pocket.) How much do you think that replacing the 4 O2 sensors should run?

I just had the 60,000-mile scheduled maintenance done; keeping that in mind, is there anything else I should have them do as long as they are replacing the cats?

As always, many thanks in advance to everyone out there for their replies.

I think the o2 sensors are around $65 a piece. I wouldn't replace them unless their bad though.

if it's not covered, do it yourself.... i know it's easier on my zetec, but it's always good to save money. o2 sensors

Your thinking like I would. Since theres not going to be any labor charge to replace the O2's, why not replace all (4) of them. This way you know you have brand new everything in the area I say whats $250 for peace of mind, compared to about $550 if you had to buy them and pay for labor down the road. Good luck to you.

Why not just replace the two downstream sensors. That's where all the O2 sensor problems seem to come from. John

The upstream sensors are the ones that usually go bad and they control the fuel trim. the downstream sensors are just to warn of bad cats- they control nothing.

roger is right. the fronts are ususally the first to develop faults.. but it's because the pcm ignores input from the rears until specific operating conditions exist. Since the fronts are monitored all the time, a failure there would be detected first.

I would't replace them unless they are bad.

Also, you should expect to pay some additional labor because there is more work. The additional labor should be minimal though.

But isn't the one up near the firewall a royal pain to change?

no - its very easy to replace o2s11 (the one by the firewall). raise the vehicle, take loose the two rear subframe bolts, pull the subframe down a bit and shove a block of wood in to hold it, the reach up between the frame and the body with a 7/8 open-end wrench.