PO420 CAT. EXPENSIVE CODE!!!!!! 2005 VIBE

[mango02]

PO420 looked at everything sensors, replaced plugs, no leaks but code returns after 30 miles going to replace CAT. There are different CAT's on the market some JUNK? and others good where do I go EBAY? ROCKAUTO? Does anybody recommend a brand or a stay away from? Exact fit please. 2005 VIBE 162,000 miles.

[Mark]

Does your state do emissions inspections? I had the same error on a 2000 Corolla I have. I used a pair of spark plug non-foulers. Drill the bottom of one out with a 1/2 bit so the end of the sensor fits in. Screw that into the other non-fouler. Screw them into the O2 sensor (post-cat) opening. Screw the O2 sensor into the new fitting. Problem solved.

[vibrologist]

How many miles on your Vibe? Did you get a tune up lately? Is there a chance the cat got fouled up?

P0420 means the catalytic converter is less than 95% efficient as it warms up. Once it is hot enough the efficiency goes up. Some have found that the converter got dirty and they put it into a detergent solution over night to wash the dirt out. Scotty Kilmer on Youtube proposes using 1/2gal of Lacquer Thinner (NOT PAINT THINNER!!!!) to 1/2 a tank of gasoline and driving the car at highway speeds for about 100 miles. Keep rpm' s below 5000. If there is dirt it is possible the solvent blows it out. If there is no dirt than you lost some time, fuel and lacquer thinner.

Also, this code is based on messages by the HO2 sensors, most likely the downstream sensor. If that sensor is on the fritz it could trigger false alarms.

If it works, that's great. However, you should ask yourself where that dirt came from in the first place and fix that as well. Oil? Coolant? EGR?

[sideshowalan]

Most muffler shops are happy to cut out your old cats and weld in some universal replacements.
It's cheaper than a direct fit cat.

[Salsa Guy]

^^That's what I did.

[mango02]

I do not want to rig a turd, no universal fix it right and not have to do it next year again. Trying to fit a universal Cat. under the VIBE and look right is not easy stuff Cat. hanging down under the car no heat shield. Would like to know what kind of Cat. is good? several people have bought MAGNIFLOW and they had to change it again within months.

[mango02]

I will try MARK's idea of the plug fouler. Sounds like a good invention.

[Mark]

Also, this code is based on messages by the HO2 sensors, most likely the downstream sensor. If that sensor is on the fritz it could trigger false alarms.

I'd like to point out that the anti-fouler trick is not a long-term fix, just clears the code until you get around to resolving the problem. On a 2000 Corolla that burns a qt of oil every ~6-800 miles it's permanent for as long as the car lasts, on an 05 Vibe I'd want to fix the problem. But if this clears the code then it's likely that the O2 sensor is still good and the cat is plugged.

[lannvouivre]

Has nobody tried Walker exhaust?