Contour Enthusiasts Group Archives Forums General Troubleshooting CEL P0420 - What are my options?

Well, the CEL has come on twice in the last two weeks so I got it checked at Autozone. Shows up as a P0420 - Catalyst System Efficiency below Limit - Bank No 1. No symptoms other than the CEL.

Edit:
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Just realized I meant to give some more info... It's a '99 SVT with 42K on it. KKM intake has been on for about 8 months and just had a SHO Shop Y-pipe installed about 3 weeks ago.
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So what are my options?

Thanks,
Jay

The description that you list sounds like a Lean Air/Fuel code... Correct me if I am wrong... If you have an aftermarket intake system (KKM/S+B..) you may want to use the stock (or buy for $5 from BAT) screen diffuser before the MAF. Sorry if I am up the srong tree.

Actually the code is intended to indicate one of the pre-cats going bad according to bank number. It may also indicate an o2 sensor going bad. Other things to look at are a broken exhaust system, exhaust leaks etc.

Hope this helps a little.

Ah yes the dreaded P0420. I have it myself. You can clear the code but it will come back. It could be the O2 sensors as that is what is being used to interpret the operation of the precats but not likely as they are checked during the driving cycle by the onboard computer.
However given the prediliction of the Contour, Mystique, Mondeo to eat cats (see recalls for earlier models), (Ford should have given the car a canine name)I would suggest that the main problem is that the Ford engine management system programming is typically running too rich a fuel mixture in general which ends up burning too much fuel in the cats and shortening their life considerably. This is the main reason why catalytic converters die. Thus it is not a cat problem as the root cause but a poorly programmed engine management system that does not account for degradation of engine components and defaults to a fuel mixture that is incompatible with the capacity of the converters. Ford cannot blame poor maintenance by the owner. This is happening in very short time spans and without O2 codes showing up as well.
I would recommend having the components governing fuel mixture checked and changing the cats (use a remanufactured set, ~500 US). However Ford needs to take some responsibility here.
I would suggest that we place pressue on Ford to do something regarding its poor fuel mixture algorithms as it seems to kill cats which may be in conflict with EPA intensions and guidelines. Ford cannot place a higher reliance or dependence for emissions control on the cats than on the engine management system, knowing that they will fail after X amount of statistical miles and expect the consumer to look after it. That is being a very poor corporate citizen. A class action lawsuit may be in order.

I would agree with the above... Dying downstream 02 sensor or pre-cat for that bank. The pre-cats should be covered for the 80K mile emission system warranty. Might want to remove the KKM before asking the dealer to cover this under warranty. If you're paying, you'll have to search around to find anything but the regular Ford factory pre-cats, and they are expensive! If you have a healthy main cat, this is a good reason to gut the pre-cats.

So, Scott, are you saying that the cats are covered under warranty up to 80k? Is this handled thru the dealer or someother channel?

Also, my main cat is healthy. I just put it on with the new SHO Shop Y-pipe. So what's involved in gutting the pre-cats? I'm not really up for replacing them given the cost unless it's covered under warranty.

Are there any issues with just living with it?

It truly is amazing that Ford would do something like this knowing that their consumer is going to pay the price. Guess their not too concerned about repeat customers.

Not feeling the happiness,
Jay

Almost sure the dealer will want to replace the O2 sensor first. Let them do that, with the caveat that they reimburse you if the CEL comes back. Or, do it yourself and save the receipt, then go to Ford for the cat. That O2 is simple to replace.

The cats in the manifold are covered under a 8/80 warranty and a bad one should be replaced free of charge by any Ford dealer. If you let it go, it *could* start to disintegrate and clog up, and that's not good at all.

Know a local dealer that won't completely freak over mods? Pretty sure to get grief over the Y pipe, even though it should have no bearing on pre-cat failure.

If you want to gut the pre-cats, you should remove them from the car or risk the motor inhaling a bunch of ceramic dust. Take a look at the rear manifold, and you'll know why I am replacing my bad pre-cat (same code) with a junkyard manifold. If I take the rear manifold off, headers are going on!

PA 3L SVT,

Thanks for the info. I have both the stock intake and Y pipe so I can easily put them back in place. I agree the Y pipe couldn't possibly have anything to do with pre-cat failure, but we all know how dealerships operate.

So are you going to gut the pre-cat on the junkyard manifold or are you going with the belief that it's still good and will last a reasonable amount of time? In line with that... does it make sense to gut just one pre-cat or do both need to be done at the same time?

Also, given your comments I'm assuming that bank 1 is the front manifold and therefore, the easier one to get to. Is that correct?

Thanks again,
Jay

FYI,

My 1998 Warranty guide specifically states the vehicles with California Emissions systems have a separate 7/70 warranty on cats and a couple of other items. 8/80 does not apply to these vehicles.

I believe the emmision system has to be built to last for a certain expected life or something like that per EPA Regs. It was 80K for TN, So your pre-cats might be covered by a manufacturers warranty. I would suggest putting the car & exhaust back as close to stock as possible, or the dealer may refuse the warranty coverage. Good luck!

Gutting the pre-cats is a messy job requiring pretty much a complet removal of the exhaust system. A search should bring up several recent threads on this.