CEL code: P2A00 er
 

Recently just got this code throw a few weeks ago. I had an exhaust leak at the time (invidia issues) and got it all fixed up. Took it to a shop to verify no leaks and all was well. Cleared the code and about a month later it came back.

I've read as much as I could on the P2A00 code on these forums, but it seems no one has any definite fix or reasoning to why it happens. Seems this code comes in pairs with P2A03, but I have not had that thrown at all. I've checked my afr that the wideband in the car sees while driving and everything looks pretty normal.

Anyone have any idea or fixes that have worked for it? Test pipes have a J bend on them and have never thrown a code before (although, that could be due to my tuner shutting them off and all).

Mods are in my signature. Car seems to be running fine based on any of the logs I have seen.

I had that code with the ART pipes. The O2 sensor wasn't reading correctly bc they stuffed too much steel wool in the o2 bung. Code went way when we took all of the wool out.

Try taking some out or put some in to see if that makes the O2 sensor happy.

I thought those 02 sensors gave a p0420 or something instead?

If that's all it is, Im cool with just erasing the code as it happens. Well, until I do an oil change, then Ill throw some steel wool in there.

P0420 is where the ECU detects that the catalytic converter is not functioning properly(missing) based on rear O2 readings.

P2A00 appears to be (looking at the service manual here) where a fault is detected in the front (A/F Sensor 1, bank 1) sensor. Possible causes include bad sensor wiring connection, bad sensor, vac leak, fuel pressure, fuel injector.

That's what I've been able to find on it, but I read a few people have had the same issue but not a single one has been able to fix it. If they did, I have found a mention on it.

It started around when I had an exhaust leak after changing the flex pipes out as they were leaking. Seems unrelated though based on the description. Seems like replacing the sensor would be the easiest. Any idea where this sensor is located?

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Mines doing the same thing I've checked alot of things out only problem I found was the pcv resonator had a small crack which could be the vacume leak?

That may make sense. I will have to check it out because i noticed with the install of the gen3's there area where that connect to the pipe is bent really weird!

Update: checked that area and saw nothing. The frustration continues...

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yeah replaced that parts and still have the code

What's weird, is I heard of people getting this when they installed motordyne artpipes I think.

Is it possible it's a leaky gasket from the header to test pipe? If not, does anyone have any idea where the front 02 sensor is located?

It's possible that either the wiring is damaged (happened to me from a stray rock on 2ndary O2) or the sensor itself is bad. Primary O2 will be located somewhere upstream of the cat -- shop manual should have a diagram.

It's also possible that the shop damaged the O2 sensor or didn't plug in the connector all the way when they dealt with the leak I suppose... not sure if erratic fuel trims would set it off too, which could be due to MAF's moving around (if aftermarket intake) or vacuum or exhaust leak anywhere before or just after the primary O2's.

the upstream o2 sensor is located on the header itself. if you look down from above the engine you will see the heatshield of the header then look where it stops and you will see a wire running into the sensor directly on the header where the pipes all blend together. this sensor is almost impossible to remove after it is heat soaked/seized to the header. if you did not touch the header then dont worry about it because chances are it is still good. the lower can be damaged very easily with installing test pipes. suggest doing the same as mentioned above before replacing because these things are expensive but not as much as the upper ones.