Lexusgs: @ ZIM DRILL - I have watched such videos many times over. My case in- point is that, whatever got cleaned by terraclean either the catalytic converter, blocked injectors or other stated reasons for getting the P0420 CODE. After my vehicles got cleaned, the codes no longer appeared on the ECU.

shadows*:
Hello car experts.....I have been battling with theses codes - P0420 (bank 1), P0440, P0441, P0446. I use Toyota Corolla 2003. I have changed my O2 sensor. But the light came back on almost immediately. Kindly help explain the codes and possible solution.

shadows*:
Hello car experts.....I have been battling with theses codes - P0420 (bank 1), P0440, P0441, P0446. I use Toyota Corolla 2003. I have changed my O2 sensor. But the light came back on almost immediately. Kindly help explain the codes and possible solution.

JaaizTech: [b]From what I have read the P0420 is a common problem in hondas.I am calling out to the gurus (Siena & Co) here, to save me and many others like me.
My Car keeps reporting an OBD code P0420 (Catalytic Converter Inefficiency), and in addition my car seems to lose considerable power especially when driving with AC. Also I have poor fuel mileage in the neighborhood of 15 MPG inter-city drive with AC on

I disconnected the dash board fuse connected to my A/F sensor and my car seems to have more power and of course consumes even more fuel. That gave me the incline that my A/F sensor and/or O2 sensor may be bad. I have made a lot of research and I have been able to narrow down the Potential problems to bad O2 SENSOR and Air / Fuel ratio sensor OR Bad Fuel Pump OR Bad Catalytic converter.

Now, here is where my issue lies: I have got seriously limited budget and hence can not afford to replace all parts especially when there is a chance that only one if faulty. Can you advice me from your experience on similar issues. Also how important is it to replace my Spark plugs, they are not really showing any major signs of under-performance.[/b]

nissparts:
If you have a catalyst code and you replace an o2 sensor, 99% of the time you would have wasted your money

cardoctor:


Not true. I had an Acura MDX that came to my workshop yesterday with the same code issue and once we replaced the o2 sensor the check engine light went permanently off and the code never came up again.

Car-Doctor.

Chikebrain:
I used to have same error on my camry 05 i4. I bought another catalyst converter but the sensor wire cut and my mechanic fixed the sensor on the previous catalyst converter to the one I bought. No code came out for about a week. The check light came on and when I scanned it I got the P2423 (HC Adsorption Catalyst Efficiency Below Threshold Bank 1) code. I've changed spark plug, cleaned out injector, checked if there's a leakage in the exhaust but everything seems to be fine. My issue is the fact that my fuel burns out quickly.

My question: Could the 02 sensor be the cause of this P2423 as I put the old one. Would I get better fuel efficiency if I change it?

Didn't want to start another thread as this thread could serve as a fountain of knowledge for related issues


CC Nurey, Gazzuzz

JaaizTech:


My P0420 code have disappeared for over 2 weeks now; this happened after I refilled my tank with Petrol and added a Mobil Injector Cleaner (Mobil power), when I noticed it the first time, I refilled my tank again when it was half-full adding another bottle of the injector cleaner (Mobil power). The code is yet to re-appear since then.

I remember in one of the videos, that the mechanic advised you empty about a gallon of "thinner" into your tank first before deciding to remove it for a wash. Perhaps the Mobil power just did the thinner's job. I will keep you guys posted if it shows up again.

jpphilips:


catalyst inefficiency has nothing to do with the sensors. its road side mechanics that suggest those crap.
connect your OBD2 and switch to the spectrum graph mode you will see the performance of your sensors. if it goes bad, another code will pop up indicating bad sensors.

what you guys ignore is this; when the catalyst degrades, it is the sensor that sends the signal to the ECU before the check engine light turns on, now, how would you have check engine for catalyst and still say the sensor that alerted you is bad? does it make sense?
exactly what my mechanic told me but i ignored him.

i had catalyst inefficiency i came here and opened a thread, i got all sorts of advice till the catalyst burned off, my exhaust hollowed and my fuel consumption improved greatly.
though the wuuu! exhaust sound bothers me but the fact that i save fuel is worth it.

skotch:


Please I'm having fuel consumption issues with my Lexus ES330, the catalytic converters were removed and I thought it'd be better to disconnect the O2 sensors but the consumption is still high.
Do you think that getting an O2 sensor spacer and reconnecting the O2 sensor will help reduce the fuel consumption?
Please do you have any suggestions for me on how to solve this problem?

cardoctor:
Good stuff but you can only carry out these procedures if you still have a cat in your exhaust system as most cars that have come into my workshop with emission related issues have had the cats gutted out from the casing.

I just had a 2008 Honda accord come in last week with the same p0420 code and on further investigation discovered that all the catalytic converters have been cleverly removed making the car less fuel efficient and the sound from the exhaust very hollow.

I must advise that you check your car's cat before leaving it for too long at a mechanic workshop.