I have 2007 forester with 49000 miles I am reading code P0420 anyone has had any issues with this.

Haven't heard of that on anything that new yet.

It's a very common problem on older cars. The causes vary form faulty sensors to plugged catalytic converters.

At that low mileage, you are covered under federal mandated warranty for any emissions related part on the car, take it to a dealer and make them sort it out.

Haven't heard of that on anything that new yet.

It's a very common problem on older cars. The causes vary form faulty sensors to plugged catalytic converters.

At that low mileage, you are covered under federal mandated warranty for any emissions related part on the car, take it to a dealer and make them sort it out.

Agreed! Let the dealer replace the catalytic converter if that is what is needed (code is usually for bank 1, i.e. passenger side, below efficiency). It's not a cheap fix. Subaru mechanic suggested to me that damage to the cat is related to the ethanol additive in the gas but do you get that additive in Fla.?

one important point - this code means nothing and does not cause any issues nor is there any mechanical concern about ignoring it for the remainder of the time you own the vehicle.

 

like they said - take it to Subaru. it's sort of a debacle of an issue to work through sometimes.

 

a small exhaust leak can cause it.

sensor might fix it.

 

there's a cheap $5 fix that ensures you'll never see that code again as long as you own the car 99% of the time. many of us do that for systems that don't respond to simple exhaust leak check and sensor replacements. .

Catalyst warranty is 8 years 80,000 miles on that car. Its possible the car is past that so if it is the dealer isn't the place to go if the cats are failing. It needs to be properly diagnosed to be sure and not waste money. Often I recommend replacing the front Oxygen sensor if the car is near 100,000 miles, reset the computer and see if the code comes back. This can be at or near the same price as a professional scan and diagnostic and I consider the front 02 preventative maintenance like spark plugs. Also make sure the air filter and air intake ducting is free of leaks.

OP said MY 2007 and 49,000 miles. That should be within the 8yr/80,000mi warranty?

Yes. I was providing information for people that search and find this thread in the future.

The cruise control will lockout with the Check engine light. This is normal for this model year. I believe its to encourage repair of the car for the light as a majority of people ignore this light.

I have this code and a virtually permenant CEL. I figure its the rear sensor needing replaced on the exhaust. Car has 148,000 miles on it and this has been an issue for last 20k at least. I changed the front O2 sensor at 100k hence why I figure it needs the rear now. Always passes the annual test over here (MOT) including emisions test so i know its not the cat, or at least not in a measurable way. But a car that young as others say should be warranty covered - so its one for the dealer. Be interesting to find out what they say/ ho they reapir it.

Yes. I was providing information for people that search and find this thread in the future.

 

Shawn,

 

Thanks. You are correct, if someone with 10+ys or 200k comes searching for a P0420 code and doesn't read the original post, going to the dealer would not be my first choice!

And what is the $5 fix?

thanks

And what is the $5 fix?

thanks

 

A spark plug non-fouler. You can buy them at most auto parts stores for about $3-$5. I think the sensors use 14mm thread.

Search here too. If this is the "catalyst below efficiency" code I've had excellent luck with Seafoam.

 

And frankly have never had a car Seafoam and/or a non-fouler didn't "fix".

The $5 fix is likely to fix the problem. It is no guarantee. Just ask my check engine light or my anti foulers.

Search here too. If this is the "catalyst below efficiency" code I've had excellent luck with Seafoam.

 

And frankly have never had a car Seafoam and/or a non-fouler didn't "fix".

For the record, please describe. Did you just add Seafoam to the gas tank or did you feed it through one of the intake lines?