How to know when a catalytic converter is really not working

[sidnau]

My problem is my catalytic converter turning on the Check Engine Light even though my converter is keeping HC and CO emissions very low. My 2003 Matrix (1ZZ-FE engine) is storing the P0420 code (catalyst system efficiency below threshold). The Toyota dealer in Tuscaloosa, Alabama re-programmed the car’s computer according to the Technical Service Bulletin EG026-04 repair procedure for a converter that has turned on the CEL. I have had the car tested twice at the Tennessee state emissions inspection station in Memphis, and the car passes easily (HC at 1.0 ppm [standard is 220.0] and CO at 0.0 % [standard is 1.2]. After the second emissions test, I cleared the P0420 code and about 150 miles later, the code was stored again and the CEL turned back on. How can I find out why the CEL is turning on? How can I find out if my catalytic converter is really not working properly?

[Wholemilk]

that might be a problem but the cat is covered for 8yrs or 80,000 miles and since no matrix out there has passed the 8 yr mark they should be covered (unless you pass the mileage). so take it to a dealer, have them look at it, if it is indeed the cat they are required to replace it free of charge.

[sidnau]

I need to depend on the Toyota owners to help me with this problem. I need to know how to find out if I really have a problem with my converter. My Matrix has been driven 160,000 miles, so the converter is out of the 80,000 mile EPA warranty. The car seems to be running fine, but the possibility that the converter is failing has me worried about possible longterm damage to the engine. The Toyota replacement part for my converter is the only converter that my muffler shop (or the dealer) recommends for my car, and the cost is about $1200. The warranty on the replacement converter is only 12 months. Thanks for your response.

[ShawnM]

The only things that set that code are the downstream O2 sensor being stuck high, or a bad converter. An O2 sensor being stuck is not very common. Its more than likely that you have a bad converter. It may pass ok after its warmed up in the state tailpipe test but that dosent mean its not still weak, especially with the kind of milage you have on it. Also most newer cars have the downstream O2 sensor placed at the halfway point in the converter. So it the front half of the converter is getting weak the computer will still turn on the check engine light even though the emision level may be ok at the tailpipe. Its very rare that a p0420 is anything other than a bad converter.

[new echo owner]

If you have an infrared temp gun or a surface temp probe capable of up to 700 degree, you can check the inlet and outlet temp of the Cat. With the engine at a steady rpm around 2500, the outlet should be at least 100 degrees higher than the inlet. If not, the Cat isn't working efficiently. If the outlet is 'cooler' than the inlet, the Cat is not working.

A bad pre-Cat A/F sensor or O2 sensor can cause a P0420 code too.

N.E.O.

[sidnau]

Thanks for your response. Your sound like you have studied converters and maybe you have studied Toyota converters quite a bit. The two Technical Service Bulletins for the 2003-2004 Matrix converters recommend a "replacement converter" instead of putting in a new "original equipment" converter when the PO420 code gets set, even though the "original equipment" converter is still being put in new Matrix cars.

Do you know anything about whether the "replacement converter" is a good idea or not, and why don't they put it on new cars?

Do you know any ways to keep a Toyota converter from going bad? If I put a new Toyota converter in my car, the warranty will only be 12 months.

[sidnau]

Thanks a lot for your suggestions. I may "go crazy" and try to get my Toyota dealer to do the checks that you describe.

[new echo owner]

From what I understand, the replacement Cat mentioned in the TSB was used to address an additional issue beside the P0420, sulfur smell from the exhaust. The 'metals' that were used inside the Cat were a bit different than the general replacement Cat if the vehicle is not experiencing a P0420 or the sulfur smell.

Aside from keeping the engine properly maintained and using the 'correct' type of fuel, that is about all you can do.

N.E.O.

[MyTrix]

I had a 420 code as well on my '03 with 84,000 miles. The dealer quoted $1300 for a replacement cat but I couldn't bring myself to part with that much. Service told me that I don't live in an 'emissions' state (Indiana) and the cat failure wouldn't hurt anything on the vehicle.

I reset the CEL twice; once by the dealer and once at Autozone. Both times the CEL came back within two weeks.

I finally seafoamed the engine through the brake booster line and reset the ECU by disconnecting the battery cables for 30 minutes. When I started Trixy up, she smoked the entire neighborhood for 20 minutes and I had residual smoke for another 20 miles down the road. Apparently,she was a very dirty girl...

It's been over a month and no CEL and she runs a lot better. May be something you want to try. A $6 can of seafoam vs a $1300 cat...

good luck

[ShawnM]

Seafoam is worth a try. We use something similar here from a company called BG. It may help clean out the converter and make a difference, or it may not do anything. It just depends on what condition the converter is in. Dosent hurt to try though.

[anita]

rotton egg smell

[myt4cyl]

I just called Toyota about my car emitting that smell...I thought that it was "burning carbon" because I only noticed it when I got on it.

I blamed it on being new, but 32,000 of mixed driving should break in a motor (still like new, but broken in).

They told me that it is probably bad gas. I wanted to inform them that I had not taken my car to a fast food joint, but figured that it wasn't the time for humor.

I will drive it through this tank of gas, fill up, and try again (knowing it will stink), and have them look at it (and take a stink-free loaner home with me).

Thank you for your posts!

[XR2003]

Originally Posted by myt4cyl

I just called Toyota about my car emitting that smell...I thought that it was "burning carbon" because I only noticed it when I got on it.

I blamed it on being new, but 32,000 of mixed driving should break in a motor (still like new, but broken in).

They told me that it is probably bad gas. I wanted to inform them that I had not taken my car to a fast food joint, but figured that it wasn't the time for humor.

I will drive it through this tank of gas, fill up, and try again (knowing it will stink), and have them look at it (and take a stink-free loaner home with me).

Thank you for your posts!

sounds like the metals inside your cat. converter is going bad.

my condolences. .