Hello and some help
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Joined: Apr 2008
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Hello and some help Hello everyone this is my first post on this site but I am a long time visitor! I currently have a Saab 9-5 and I will be getting rid of it in a month or so when I graduate school and I will be purchasing something with a ls1. Any way I have a question about my Saab which has had a CEL come on last night and the code was p0420- catalyst efficiency below threshold bank1. I believe that to be an o2 sensor but I could be wrong. Thanks for your help and I look forward to finally being a member.
BTW I have owned the Saab for 5 years and it was done me well, I would it got its money out of me
but I will be gland to see it go so I can get the car I have always wanted.
BTW I have owned the Saab for 5 years and it was done me well, I would it got its money out of me
but I will be gland to see it go so I can get the car I have always wanted. 
Thread Starter
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Joined: Apr 2008
Posts: 3
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I can understand it, but for those who cant, what would cause a Check Engine Light with a code of p0420-catalyst efficiency below threshold bank 1? My guess is an o2 sensor. The car that gave this code is a saab 9-5 v6 turbo. I know it is not an ls1 but i have been reading these boards for years and everyone seems pretty intelligent and willing to help. My car is for sale and I will be purchasing something that is ls1 powered. Thnaks for your help I hope this is easier to understand.
Found the following for you:
Catalyst System Efficiency Below Threshold (Bank 1)
What does that mean?The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.
Hope this helps!!
Catalyst System Efficiency Below Threshold (Bank 1)
What does that mean?The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.
Hope this helps!!
Thread Starter
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Joined: Apr 2008
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Yes it helps a bit, I forgot to mention that I have a hi-flow cat on the car, its been on there for about 3 months or so and I think the car finally noticed. I am going to see if there are o2 sims available for the car. Any good places to look?
