My sevice engine light came on today coming home from work.i plugged my Diablo predator in and the code I read is P0430,cat efficency below threshold,bank 2.I have high flow cats installed and this is the first code I have got since they were installed.Is my o2 sensor bad? Is the cat bad? Is bank two the left or right side of the engine? I'm not quite sure whats wrong or what I need to fixThe high flows have been in my truck for 3 months,I dont think they're bad,my truck runs great.Any help or info.would be appreciated,thanks,

 

Bank 2 is on the driver side. Without seeing the readings on a scanner of the rear O2 this would only be a good guess but a new rear O2 on the driver side would probably take care of it. I would also recommend disconnecting the battery for 30 mins. to reset the computor. Another thing I would do is clean the MAF while the battery is disconnected.

 

Thanks torkum,I thought it was an o2 sensor also,do the high flows allow the sensors to read "false" or incorrect data turning on your cel?I read one post here a while back where one guy said his high flows were "eating" up o2 sensors at an alarming rate,he said he has installed 3 new ones in a year in his truck,I told him there is probably something else wrong and the bad sensors are the outcome.Thanks for your time and info.,its greatly appreciated.

 

With all due respect to Torkum, I'd suggest NOT replacing any O2 sensors yet.

The catalyst monitor is fairly robust in its ability to verify proper operation of both the up and down stream O2 sensors before running the monitor test.

My best suggestion is to use a scan tool or PC-based graphing tool to look at the upstream vs downstream switch rates and to view how clean (or ragged) the sensor outputs actually are. You can actually see the outputs changing in real time and can easily identify a marginal sensor or if the cat is dead or dying.

If you already have a laptop, the interface with software is only around $125 for the basic edition needed for your current truck and is useful for most OBD-II diagnostics. I happen to use the setup supplied by Alex Peper.

Another trick is to, if space allows, install the downstream O2 sensor on a sparkplug anti-fouler. This backs the sensor out of the direct exhaust flow and causes it to have a small, relatively stale pool of exhaust gasses at the sensor element. Plus, they're only a couple of bucks. Some modification might be required... Be sure to use anti-seize....

Steve

 

Steve,I really appreciate your post.My cel came on Tuesday,I read the code and cleared it,well this morning it came on again,so I'm postive its the sensor.I have the high flows on my truck and they have only been on about 3 months,can a cat go bad in that short a time?my truck runs great,but from what I read this code (P0430) does not affect performance,only emissions and fuel economy.Thanks again for your post,I'm going to try the spark plug non-fouler adapter,I would have never thought of that,what a cool trick,thanks again.