Hey guys, new here and unsure if I posted this correctly: Just bought myself a gen 2 with 225k miles, Getting an engine warning light, used the Car scanner app along with a bluetooth OBD reader (this is brilliant). I'm getting P0138 which is oxygen sensor 2 high voltage, Piency below thres0606 which is engine control module/ powertrain control modul and P0420 which is cat effichold. Am I right in thinking all three are likely be caused by a fault lower oxygen sensor? Is it likely to be a dodgy cat? I'll be out tomorrow with a multimeter to check on the sensor, but would love your opinions and advice!
Make sure you're 12 volt is up to the task It's not dipping below 12 volts if you will You have the oxygen sensor code most people usually have the PO420 because the catalyst can't pass the internal test run by the car whenever it does it don't know don't care it just does apparently you can't fool it but you do need to look at the sensor in question and check its voltage obviously you're going to have your multimeter out so this is the plan I'm sure I could see replacing the downstream oxygen sensor at this kind of mileage The upper ones I think usually last kind of forever I don't think it's the other way around but either way I'd give it a whirl A lot of times in these O2 sensors we're looking at here it's the heater circuit that's gone bad so that necessarily doesn't make the oxygen sensor bad it just doesn't have the preheat capability and I guess could set the light and so on but the sensor part should work when it's near or at temperature It just doesn't have the heater that's the code as the voltage is the problem but I think your PO420 code may stay and if you don't have to do anything about it it's not affecting your car or mileage at all I've been driving one vehicle with the 0420 code for 5 years or better now matter of fact that cars have the catalytic converter removed a straight pipe installed the O2 sensor bung is still in place in the sensor screwed in I need to space it out and reset and see if that works where I live I don't have to have the cat You may be that lucky in the UK I don't know
thanks for getting back to me I wouldnt have thought to check the 12 volt! Do you think it could be linked to the ecm code? Also i dont believe they do emissions tests on Prius's in the UK, so sounds like I can ignore the cat? will it affect fuel economy?
No mine hasn't had any effect on fuel economy with the cat removed or the cat in place and just out of spec doesn't seem to make any difference on mileage and like I say you need to have your 12 volts with amps behind it that it needs to have to keep all the computers booted and you know that runs your headlights and your fans and everything or a lot of stuff and then it's charged by that puny circuit in the inverter I mean it's a really not very well made charging system for your 12 volt No one drives enough to keep the 12 volt charged up so you either tender it or you replace it a lot. The heat circuit in your oxygen sensor needs 12 volt It's a heater for goodness sake so it's going to use some amps pretty decently I imagine but not for long so see what happens with the 12 volt and all that Make sure that is no question correct clear the codes you know what they are and then see if they come back especially if you had to do anything to the 12 volts
Could be the lower (downstream) sensor or the upper sensor. It can set the ECM code if the two sensors disagree with each other. If either sensor has problems, then you should ignore the P0420 until they're fixed, as the catalyst test uses both. Posted via the PriusChat mobile app.
