2005 S60 p0420

asummers · Post by **asummers** » 10 Aug 2015, 09:42

We have had this code for a little while now, "p0420 catalyst efficiency below threshold bank 1". The car runs rough at lower rpm's. This would be the catlytic converter I believe. Does the bank 1 mean it is the one located right at the exhaust manifold at the engine? Any advice on this? Since my area does not emission check vehicles could the converter be removed and would that correct the rough running? Thanks.

carlsson72 · Post by **carlsson72** » 10 Aug 2015, 10:20

I don't think it's wise to have it removed...it's an integral part of your emmision system..you car's ecu might make all sorts of adjustments to compensate if you get it removed resulting to more problems in the future...just my opinion...let's wait for what experts say.
I have the same code on my other car...not a volvo. It happens everytime it's cold..on warm months never comes out..i just clear codes,it doesn't affect my engine performance.

Post by **chrism** » 10 Aug 2015, 11:08

Does it not seem odd that the bank 1 (upstream) sensor would be the one reporting bad catalytic efficiency? Or is it saying that an inefficient cat is the EFFECT of a bad bank 1 sensor?

I saw a Youtube video where a guy used an infrared temperature sensor to compare the exhaust pipe temp at the cat inlet vs outlet. A good cat will show significantly increased temp at the outlet compared to the inlet.

That being said, if your car has never had an O2 sensor replaced in its 180,000 mile life, I would tend to try that fix before ripping the cat out. Cats are expensive and I'm of the belief that the OE Volvo ones are far superior to any of the aftermarket units. Also, if you do decide to replace a sensor, examine the original one for the manufacturer's stamp and go with same brand in the direct fit "plug-n-play" configuration.