Code P0421 catalytic converter

That system should be working in about 45 seconds to a minute. You can see it starting to get warm in the third frame. What you don't want to see is that last frame.

Hello again.

Yes, it's very simple and effective. I've used it numerous times as I've stated. All you do is buy a cheap Hudson sprayer from home depot for $10.00. Just remove the pre-catalytic converter Ho2 sensor and spray the contents into the exhaust pipe. I've attached a picture of a Hudson sprayer below. Hope this helps and keep us updated as what you decide to do. Thanks again for using 2CarPros.

Danny-

Usually you don't get the classic symptoms if the system has dual converters like yours. They only monitor the upstream unit on many vehicles like that. So the upstream unit starts to go bad, but the second unit still cleans up the exhaust. Plus from the way yours is acting it is still working a bit, just not enough to keep the sensors happy. I have seen many other failed converters that show none of the classic signs either, if the engine is running correctly and in good shape many times you see nothing. Usually the signs are really the issue that made the converter fail in the first place, like bad piston rings that were causing the engine to burn oil, but the smoke was cleaned up in the converter, or the bad injector that caused the converter to burn up and now you smell the rotten eggs and see the black smoke of a rich running engine once the converter finally fails.

You don't have to replace both. The front one is the only one that has sensors. The rear one just goes along for the ride. If you look at where the O2 sensors are sensor 1 is before the converter while sensor 2 is in front of the second unit in the pipe between them. If they did tailpipe sniffing then maybe replace it if you fail.

Hello again.

Well, it might be a long shot to try the liqui moly to help save you money as opposed to buying new catalytic converters. Yes, they can be quite expensive so I understand your dilemma. Keep us updated as to how things turn out. Thanks again for using 2CarPros.

Danny-

Hello again.

All you will need to do is gain access to the exhaust pipe under your car. Just unscrew the pre-catalytic converter oxygen sensor and remove. Using a Hudson style sprayer or something comparable empty the liqui moly can contents directly into the exhaust pipe. Re-install the oxygen sensor. Directions are on the can. I believe you run the cars engine for 15 minutes to cycle through the catalytic converter. Hope this helps and thanks again for using 2CarPros.

Danny-

If this car has the dual units on it, which a California car came with, you don't need to go under the car to get to the pipe, the first O2 sensor should be under the hood in the exhaust manifold between the engine and the radiator. Then you would spray the product into the sensors bung then replace the sensor and start the engine. Do not forget to put the sensor in as the exhaust pressure could spray it all back out and cause a real mess. The downstream sensor is behind the converter being monitored in the pipe that leads to the second converter. This was a common thing on many vehicles. They would install a converter close to the engine. Then they would do testing and discover that those units were good enough for the federal requirements, but didn't do so well with the stricter sniffer testing in California so they added the second converter in the pipe farther back to finish scrubbing the gasses. On more modern vehicles they monitor all of the converters so a modern 4 cylinder can have the dual converter system but will have a bank one sensor one then a sensor 2 and a sensor 3 as well with 2 being between the two converters like yours and sensor 3 being in the pipe between the second converter and the muffler. Larger engines can be even more interesting with a couple that have 3 converters on each bank of cylinders.

Hello,

Maybe look into a programmable chip for it and lean out the mixture. I don't believe there all that expensive now.

Tom

Hello again.

Yes, I watched the video. They just used a vacuum source to introduce the cleaner through the system with the engine running. They varied the amount and increased the engine rpm's to not stall the engine out. That way is just as effective. I personally introduce directly into the exhaust system. Hope this helps and thanks again for using 2CarPros.

The P0135 is an O2 heater circuit code for sensor bank one. So it's the sensor before the converter that is giving the P0421. I would look at the wiring to it to be sure it isn't damaged or shorted. It won't be the reason for the 421 code though.

Hello again.

I will be with you in the morning when my references are working again properly. Thank you for your patience.

Danny-

Correct in that the P0421 is a bad bank one cat, the P0135 is the heater circuit for the first O2 sensor on that same converter. The two are only related in that they are the same bank.

As for the EVAP leak code, site policy is to keep different issues as separate questions to make site searches easier. So please use the link below to ask that as a different topic. Thank you.
https://www.2carpros.com/questions/new

Hello again.

I've attached picture diagnostic steps below relating to code P0135. As far as code P0421 that is a separate issue and will need to be addressed in a new question.

Here is the new question link:

https://www.2carpros.com/questions/new

Hope this helps and let us know if you have any further questions on this issue. Thanks again for using 2CarPros.

Danny-