Weird OBDII code... please help diagnose
hey guys,
took my 2000 4runner in to get an inspection and they failed me because an OBDII reading came back. P0420 is a known code and i know it has to do with the catalytic converter but the bank reference is weird... the form they printed me says: P0420 Catalyst System Efficiency Below Threshold (Bank 14). i have never heard of (bank 14). i have always just heard Bank 1 or 2 to tell you which sensor is out... any ideas? Tom |
That's a misprint, there is only bank 1 when it comes to cats on our trucks. Bank 2 emissions data is for vehicles with dual exhaust ie...4 cats, 4 O2 sensors. My BMW has 4 O2 sensors and I get obd II readout on bank 1 and 2.
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my inclination then is to just replace the o2 sensor first and if that doesn't work then look into a new cat... from my understanding though, Bank 1=sensor before cat; bank 2=sensor after cat... correct?
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If you look up OBDII codes this is what it should say for code P0420:
P0420 Catalyst System Efficiency Below Threshold Bank 1 P0430 Catalyst System Efficiency Below Threshold Bank 2 |
have you replaced an o2 sensor before? i've been told it really won't matter if i use OE or advanced auto... any thoughts?
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Originally Posted by ToyoRunner94
(Post 51039861)
... from my understanding though, Bank 1=sensor before cat; bank 2=sensor after cat... correct?
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Originally Posted by ToyoRunner94
(Post 51039866)
have you replaced an o2 sensor before? i've been told it really won't matter if i use OE or advanced auto... any thoughts?
http://www.urdusa.com/product_info.p...s_id=430006000 |
1999 & 2000 49 State manual V6 4WD; Front: 234-4161
1999 & 2000 49 State manual V6 2WD & 4WD; Rear: 234-4154 this was copied from URD... i think this is what i was referring to... see it says front and rear... so that doesn't apply to the position relative to the cat, its the position on the engine? so i would need the front? |
Originally Posted by ToyoRunner94
(Post 51039873)
1999 & 2000 49 State manual V6 4WD; Front: 234-4161
1999 & 2000 49 State manual V6 2WD & 4WD; Rear: 234-4154 this was copied from URD... i think this is what i was referring to... see it says front and rear... so that doesn't apply to the position relative to the cat, its the position on the engine? so i would need the front? |
are these codes just a guessing game or if i take my truck say to advanced or toyota, could they get further info on exactly what the issue is? or is it just kind of guess and test and see what turns the CEL off?
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Given the cost of cats, I'd probably start with the O2 sensors too. Or actually you could just install this P0420 eliminator box :hotglass: http://www.urdusa.com/product_info.p..._id=1230100014
Yeah even the dealers will sometimes just be guessing, check this out: http://www.ttora.com/forum/showthread.php?t=93770 and this: https://www.yotatech.com/forums/f2/t...verter-164833/ |
thanks Dale, appreciate the info
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the sensor before the cat is called bank1 sensor1 and after the cat is bank1 sensor2
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Originally Posted by ToyoRunner94
(Post 51039885)
are these codes just a guessing game or if i take my truck say to advanced or toyota, could they get further info on exactly what the issue is? or is it just kind of guess and test and see what turns the CEL off?
If your sensors are at 70k+, it makes sense to change them and see if it helps. They will go soon anyway. Also check for exhaust leaks as that is the other cheap(er) fix. My 99 started throwing P0420 about 25k ago but I reset it and it goes 3 or 4 months. I can see from the sensor outputs that the cats are working, but the trip algorithm must be pretty sensitive. If the trips accelerate, I'll have to bite the bullet and swap the cats; I have done the sensors. For you, I'd see how long until the next P0420. You can do the "pull the battery cable" thing and pass inspection, unless your state requires a repair invoice. Mine does. NEVER go to inspection with a CEL lit up, you are just wasting your time. Good luck... For the record mt_goat is spot on with the sensors--there is no bank 2 on a 3.4 L and sensor 1 is the A/F before cat sensor that feeds the ECU. Sensor 2 is the after O2 that is only used for throwing codes--that;s why the rear simulator works. The code is thrown based on a comparison of the two; so if there is no difference the cats aren't performing and you get a code. Dead sensors will throw other codes--merely degraded ones might not. |
I ended up buying a front o2 sensor from URD. I checked out the link Dale provided and i found a matching sensor for my truck so I figured i'd start with a cheaper fix and see if that is the problem. My truck has 122xxx on the odo and I have no indication that the sensors have ever been replaced. I had the code pulled twice at two different locations and both came back as Bank 1 and neither mentioned Bank 2 so i'm not going to worry about the rear for now. I should get it in a few days so we'll see what happens.
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There still seems to be some confusion, "bank" is different than "sensor". Sensor 1 is before the cat, sensor 2 is after the cat. Bank refers to one half of the engine and in the case of a vehicle with dual exhaust, 1/2 of the exhaust. The 5VZFE doesn't have dual exhaust so there is no bank 2 after the crossover.
But anyway, I'd probably start with the front sensor too since its the most important to engine performance and the ECU's self-tuning adjustments. If that doesn't work then try replacing the rear. |
Originally Posted by ToyoRunner94
(Post 51041766)
I ended up buying a front o2 sensor from URD. I checked out the link Dale provided and i found a matching sensor for my truck so I figured i'd start with a cheaper fix and see if that is the problem. My truck has 122xxx on the odo and I have no indication that the sensors have ever been replaced. I had the code pulled twice at two different locations and both came back as Bank 1 and neither mentioned Bank 2 so i'm not going to worry about the rear for now. I should get it in a few days so we'll see what happens.
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1999 & 2000 49 State manual V6 2WD; Front: 234-4162
1999 & 2000 49 State manual V6 4WD; Front: 234-4161 1999 & 2000 49 State manual V6 2WD & 4WD; Rear: 234-4154 these are the listings on the URD site where i bought the o2 sensor. i was under the impression the o2 sensor is what throws the emissions code p0420 catalyst below threshold (bank 1)... did i get the wrong thing? i'm confused what i should actually be getting now... |
Originally Posted by ToyoRunner94
(Post 51041804)
1999 & 2000 49 State manual V6 2WD; Front: 234-4162
1999 & 2000 49 State manual V6 4WD; Front: 234-4161 1999 & 2000 49 State manual V6 2WD & 4WD; Rear: 234-4154 these are the listings on the URD site where i bought the o2 sensor. i was under the impression the o2 sensor is what throws the emissions code p0420 catalyst below threshold (bank 1)... did i get the wrong thing? i'm confused what i should actually be getting now... |
Now that you say that, i'm not sure if i'm 49 state. i actually had it shipped in from a carmax in las vegas. is there a way i can tell where it was made?
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