03 Vibe P0420 *Need Help ASAP* Catalitic Converter issue

[Rodvibe]

I had a catalytic converter go bad so I went to a local shop which then replaced it and in less than 4,000 miles the new one went bad. I had the O2 Sensors checked by a different mechanic and they were performing properly. This indicated that the catalytic converter had poor performance. I then went back to the muffler shop that originally changed the catalytic converter and he said he would look at it; He dropped it down, cut it open and looked inside. He found 'gray blackish film on the front of the converter' about a 1/16th of an inch thick. What could this be?

He believes that there is most likely anti-freeze that is leaking into the exhaust system, but after testing his theory over a period of 6 months we found that the coolant had only gone down 2 ounces. We don't feel as though that is enough to contaminate the converter.

Two converters bad, probably caused by the same issue.
So, here is the questions. What else could cause such an issue? And, is ANYONE replacing Catalytic Converters at a regular basis?

[Salsa Guy]

How's your oil consumption? How many miles on the car? Are you running rich (excessive amount of un-burnt fuel)? How's the fuel mileage? Any performance issues? Any other codes? When's the last time you changed your spark plus, air filter, clean the injectors?

[Rodvibe]

The oil consumption is fine. We just changed the oil today as a matter of fact and after 5000ish miles it went threw 3/4th of a quart.
The car has 136,xxx miles on it.
As for the fuel mileage we are going to check it this week. Last time it was checked it was 30mpg.
There has not been any other codes and as for the performance, its fine.

At a 102,xxx miles we replaced the spark plugs, replaced the serpentine belt, removed air induction components and cleaned throttle body and throat, then reassembled. We pressure tested the cooling system, inspected the radiator, cap, hoses, belts and fan clutch. Filled and drained with water, added Flush/Cleaner and ran for 30 minutes. Drained and flushed till clear and filled with correct (50/50 mix) coolant. Inspected thermostat operation, Re-Chec. The air filter has been changed regularly.

We have never cleaned the injectors. How would you tell if it was running rich? The car isn't blowing any smoke and there isn't any signs as though its running rich.

[SeattleJeremy]

Looks like you've been very through. Has the intake manifold gasket been checked?

P0420 means it's not getting the right air/fuel mixture. Too much air, or too little air. Figure out what one.
http://engine-codes.com/p0420_toyota.html" onclick="window.open(this.href);return false;

[joatmon]

P0420 means it's not getting the right air/fuel mixture. Too much air, or too little air.

Actually, P0420 means the computer thinks the catalytic converter is not working properly. It compares the readings coming off the two O2 sensors, and if they are not different enough, it figures the cat isn't converting enough.

Over time, things such as improper mix may lead to contamination of the cat, but for a car running ok to coat a cat with a thick film in only 4000 miles, the mix would have to be so bad the car likely wouldn't run right and would throw additional codes related to the mix


Rodvibe
On a Vibe, The cat is close enough to the end of the pipe that bolts onto the exhaust manifold that you can see the front of the cat without cutting it open, so I don't know why your muffler shop had to cut yours open.
The worst catalytic converter in a Vibe experience here was that of pmh013, some of her troubles are described in viewtopic.php?t=2199" onclick="window.open(this.href);return false;. She never solved the problem, ended up getting rid of the car after the fourth cat.
In my car. cat's last about 100K-120K miles.

Is your Vibe a base, AWD, or GT? Does the car only ever get really short trips, perhaps never long enough to run at full operating temperature?

Sounds like you're at ~130K miles now, but had the cat replaced and fail again at least 6 months ago, and at 102K you had a lot of service done. Did the service occur before, between or after the two cat failures?

[Salsa Guy]

Sounds Like a GT with the air induction system.

[Raven]

Looks like you've been very through. Has the intake manifold gasket been checked?

P0420 means it's not getting the right air/fuel mixture. Too much air, or too little air. Figure out what one.
http://engine-codes.com/p0420_toyota.html" onclick="window.open(this.href);return false;

This is correct. PO420 very rarely means you need a new cat. I don't know how many thousands of people have needlessly spent a ton of money replacing them only to have the code pop up again. PO420 is the most common OBDII code.
There are many things that can trigger this code. Vacuum leak( intake gasket etc.), exhaust leak etc.

[Rodvibe]

Looks like you've been very through. Has the intake manifold gasket been checked?

P0420 means it's not getting the right air/fuel mixture. Too much air, or too little air. Figure out what one.
http://engine-codes.com/p0420_toyota.html" onclick="window.open(this.href);return false;

The manifold gasket has never been checked. How would you go about doing that?

P0420 means it's not getting the right air/fuel mixture. Too much air, or too little air.

Actually, P0420 means the computer thinks the catalytic converter is not working properly. It compares the readings coming off the two O2 sensors, and if they are not different enough, it figures the cat isn't converting enough.

Over time, things such as improper mix may lead to contamination of the cat, but for a car running ok to coat a cat with a thick film in only 4000 miles, the mix would have to be so bad the car likely wouldn't run right and would throw additional codes related to the mix


Rodvibe
On a Vibe, The cat is close enough to the end of the pipe that bolts onto the exhaust manifold that you can see the front of the cat without cutting it open, so I don't know why your muffler shop had to cut yours open.
The worst catalytic converter in a Vibe experience here was that of pmh013, some of her troubles are described in viewtopic.php?t=2199" onclick="window.open(this.href);return false;. She never solved the problem, ended up getting rid of the car after the fourth cat.
In my car. cat's last about 100K-120K miles.

Is your Vibe a base, AWD, or GT? Does the car only ever get really short trips, perhaps never long enough to run at full operating temperature?

Sounds like you're at ~130K miles now, but had the cat replaced and fail again at least 6 months ago, and at 102K you had a lot of service done. Did the service occur before, between or after the two cat failures?

The cat that went bad was the cat up front, the first one, which is why it had to be cut open. The Vibe is a Base Vibe, and average trip is roughly 17miles with a mix of freeway and city. So, I am sure it starts running at full operating temperatures.

As for the servicing we replaced the stock Cat at 126K miles and at 130K miles the 2nd Cat went bad. We went back to the service shop and he said he would warranty it. We've been using the bad Cat, trying to solve what caused the gray film, and fix this issue. It was 24,000ish miles after the servicing this started happening.



ALSO!, Just remembered a trip that I took to California. While driving into Cali the Engine light turned OFF! I live in Nevada which is high altitude, about 5000ft. This was before we changed the Cat. It went about a month, maybe less, until it came back on.

[Amoeba]

I have the identical problem with the same year and model. I'm on my 2nd cat and check engine light still comes on.
I live in Nevada too and when I drive the car down to sea level in California, the check engine light goes off. I was in California for 4 days and the whole time the CEL never came back on. Drove back to Nevada and the next morning, BAM! The CEL came back on, and it's not the California gas that makes the light turn off because the CEL came back on without having fueled up in Nevada, only Cali gas was in the tank.
I'm sure it has to do with the elevation change. The car is driven at 3000ft.
Running rich I suppose.

[circuitsmith]

Has the MAF sensor been cleaned lately?

[cegarbage]

That error message started coming up at 198k. I used an AMSOIL product and within 5 miles the check light went out. It came back on at about 203k and another container of AMSOIL turned it off. I'm not at 210 and the engine light hasn't come back on.

[Rodvibe]

That error message started coming up at 198k. I used an AMSOIL product and within 5 miles the check light went out. It came back on at about 203k and another container of AMSOIL turned it off. I'm not at 210 and the engine light hasn't come back on.

What Amsoil product did you use? Was it a gas additive or an oil additive?

[Rodvibe]

Has the MAF sensor been cleaned lately?

No I have not but I will.

[randyr316]

i just bought 03 awd vibe, and got boned with po420 code, i bought new 02 sensor ''post cat'', then i got evap code, so bought new gas cap, evap went off, then o2 popped back on, the evap and 02, so i bought new vent selenoid, the light went off by itself, then couple miles later, BOOM, CEL popped on, its po420, scanner says evap and 02 not ready? can anybody please help, before i just ghost ride this car into a tree