Catalyst System Efficiency Below Threshold (Bank 1)

[Falky100]

Hey Guys, Long story short. A while back when I had some o2 sensor issues. My former mechanic replaced my o2 sensors with non genuine ones, after he did this I still had issues and then he put a device in my exhaust that the o2 sensor piggybacked onto which is meant to slow/swirl the air and let the sensor read better (this is the sensor after the cat). Again I still had issues and after reading these forums it states that the Turbos only like genuine sensors. So I replaced the dump pipe sensor with a genuine one, and hey presto! my car seemed 100% fixed.

However on the weeked I decided to take this rediculous pice out of my exhaust and see if it makes a difference to my power or anything. And just tonight I had the orange light of death come on (Engine light). So when I got home I plugged my elm in and found this..

P0420, Catalyst system efficiency below threshold (bank 1)

and the description read - Engine travelling at steady highway conditions for 5mins in closed loop, PCM detected Ho2s switch rate was too high.

Now my first thought was, well obviously it needs the genuine sensor to read properly. But isnt bank 1 the dump pipe sensor?

And last question. Is driving around with my car "below threshold efficiency" going to do any damage?

So much for my long story short. But hey, I hope someone can shed some light on this for me..

Cheers, John.

[Falky100]

Sorry. Forgot to add. My exhaust is stock standard. As is the rest of the car besides a mild custom tune.

[ms700]

However on the weeked I decided to take this rediculous pice out of my exhaust and see if it makes a difference to my power or anything.

Feel free to correct me, but it would appear that this "rediculous pice" has indeed made a difference.

How about you replace this "rediculous pice" back wherever it belongs, disconnect the battery for 10 mins, and see what happens.

[bionicxr6t05]

The p0420 code describes a condition where the downstream (after cat) and upstream (before cat) sensors have a common switching pattern, this is generally caused by a failing cat converter (hence catalyst efficiency below threshold)

In obd codes Bank 1 and bank 2 are used to describe the left and right hand banks of a V engine, straight sixes have only one bank so they just say bank 1.

I dont know what this rediculous piece is your talking about, can u post a pic or describe it better?

[Paulie2256]

You only replaced the dump sensor right? The code you see is referring to the after cat sensor. It has absolutely no impact on the car, it is only there for emissions to tell the cat isnt working properly. As long as the dump sensor is good then you will have no problem driving around with that code.

Edited 14/08/12 09:52 PM by Paulie2256

[1600dave]

something like these?

http://www.ebay.com.au/itm/O2-Extender-Oxygen-M18-Spacer-HHO-Wideband-Dry-Cell-Sensor-02-Test-Pipe-Bung-H20-/130716275163?pt=Race_Car_Parts&hash=item1e6f4c11db

http://www.ebay.com.au/itm/oxygen-sensor-o2-02-header-bung-pipe-spacer-18mm-thread-M18-x-1-5-90-degrees-HHO-/130726837064?pt=Race_Car_Parts&hash=item1e6fed3b48

[Wenier]

So all it does is move the sensor out of the exhaust flow, would've thought that would give incorrect feedback.

[bjc]

My f6x lives with this code as there is no cat on the car...

[Falky100]

Dave is pretty much on the money with that link. Except mine is straight, not 90 degrees.

Yes I only replaced the dump sensor. There is still a non genuine sensor post cat. It is the same sensor in one of my other threads (there is a pic of it in there). And it is quite different to the genuine ones.

Would you think buying a genuine sensor could fix this problem? If so, does anyone have a part # handy?

Cheers and thanks for all the feedback

John.

[1600dave]

Not sure if it'll help or not, but get these instead of genuine Ford if you do decide to change it.

NTK make them for Ford, these just don't have the Ford stamp, and are heaps cheaper.

http://www.ngk.com.au/oxygen-sensors-part-finder?PageMode=Results&Make=FORD&Model=Falcon+BF++XR-6T&Capacity=4.0L&Year=10%2F05+-+02%2F08&Engine=&Engine=Barra+240T%2C+6FPAAAJG6+Cyl+DOHC+TMPFI+24V+240+

http://www.carpartsaustralia.com.au/product_info.php?products_id=11652

http://www.carpartsaustralia.com.au/product_info.php?products_id=11651