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I know it's bank 1 and that's passenger side but is it the sensor on the front of the car or the rear?
The one at the front by the firewall.
Check to see if your exhaust system is not leaking anywhere. The leak in the system will cause O2 sensor not heating up thus throwing the check engine light.
The one at the front by the firewall.
Check to see if your exhaust system is not leaking anywhere. The leak in the system will cause O2 sensor not heating up thus throwing the check engine light.
I have to disagree. The upstream sensor controls the engInes AFR in closed loop mode telling the ECM how things are going burn wise. The downstream sensor looks to ensure the upstream cat is functioning properly, assuming the engine is running well and doesn't have a misfire or anything else.
The suspect sensor is downstream under the car (bank 1, right side) but honestly you need to make sure there are no exhaust leaks as this can trigger this too.
I have to disagree. The upstream sensor controls the engInes AFR in closed loop mode telling the ECM how things are going burn wise. The downstream sensor looks to ensure the upstream cat is functioning properly, assuming the engine is running well and doesn't have a misfire or anything else.
The suspect sensor is downstream under the car (bank 1, right side) but honestly you need to make sure there are no exhaust leaks as this can trigger this too.
If P0138 code is for the downstream sensor passenger side and P0158 is for the downstream driver side, I figured P0420 is for the upstream ones, either passenger or driver side. I could be wrong though.
Does anyone know what Circuit High means?
Last edited by primavera; Jan 31, 2023 at 05:17 PM.
If P0138 code is for the downstream sensor passenger side and P0158 is for the downstream driver side, I figured P0420 is for the upstream ones, either passenger or driver side. I could be wrong though.
Does anyone know what Circuit High means?
High means the downstream sensors output is pinned against the rail. IDR which sensor this is (there are 3 main types) but typically it outputs +/- 1 volt max, so if it's +999mV for a couple minutes or longer, it throws those codes.
Idk how to interpret any of this but this is what I pulled from my OBD II
Originally Posted by 2013FSport
High means the downstream sensors output is pinned against the rail. IDR which sensor this is (there are 3 main types) but typically it outputs +/- 1 volt max, so if it's +999mV for a couple minutes or longer, it throws those codes.
Last edited by seanmwple; Feb 1, 2023 at 01:21 PM.
100% stock. I was getting codes P0301 and P0305. Replaced both plugs and coils and those went away. Cleaned throttle body with seafoam. I've been told this was a dumb idea but I listened to someone on Reddit who said to do it .
Later that day after doing that is when I started getting the P0420 code. I changed the o2 sensor on the passenger side but I changed the one you access from the hood not the one under the car. After i changed the sensor the code was gone for almost 3 days. Before changing the sensor the code would pop up within 2-3 hours after clearing codes.
Originally Posted by MikeFig82
You have a Rich condition going on. Look at your FUEL trims all negative numbers.
What mods do you have on the car? Catch can?, Intake?
From the drivers seat looking forward:
Left side is Bank2 - Right side is Bank1
B1S1 is the one you changed which corresponds to cylinders 1, 3, 5.
Bank 2 is cylinders 2, 4, 6. Fixing the misfire is critical. When were those readouts taken? Before the plug/coil change or after?
Becsuse you ran chemicals through it, these can loosen debris that impact sensor performance. I'd opt for opening it up to get some flow through the engine and see if it resolves itself. Getting the fuel trims normal before addressing the other codes could easily resolve them. And in this case, if the upstream sensor was bad it could have created the Rich condition Mike mentioned as well as the misfire P0301 /P0305.
Didn't you start another thread recently? What was that about?
Did you replace all the plugs or just 2? I definitely would be doing all 6 if I were there and definitely check the gap before tosshing them in. That said I would also replace B2S1.
PS P030X can be fuel, spark, or compression/timing. It is not an absolute that ignition caused P0301 / 5.
So Bank 2 is driver side underneath the car or from the engine bay?
The P0420 codes didn't come until after I change the plugs and coil. What do you mean by open it up? I changed 3 of the plugs and coils. I'll change the other 3 tomorrow.
Originally Posted by 2013FSport
From the drivers seat looking forward:
Left side is Bank2 - Right side is Bank1
B1S1 is the one you changed which corresponds to cylinders 1, 3, 5.
Bank 2 is cylinders 2, 4, 6. Fixing the misfire is critical. When were those readouts taken? Before the plug/coil change or after?
Becsuse you ran chemicals through it, these can loosen debris that impact sensor performance. I'd opt for opening it up to get some flow through the engine and see if it resolves itself. Getting the fuel trims normal before addressing the other codes could easily resolve them. And in this case, if the upstream sensor was bad it could have created the Rich condition Mike mentioned as well as the misfire P0301 /P0305.
Didn't you start another thread recently? What was that about?
Did you replace all the plugs or just 2? I definitely would be doing all 6 if I were there and definitely check the gap before tosshing them in. That said I would also replace B2S1.
PS P030X can be fuel, spark, or compression/timing. It is not an absolute that ignition caused P0301 / 5.
So Bank 2 is driver side underneath the car or from the engine bay? The P0420 codes didn't come until after I change the plugs and coil. What do you mean by open it up? I changed 3 of the plugs and coils. I'll change the other 3 tomorrow.
