I'm posting this because I understand the struggle of those of you who have had to deal with either of these P2A codes. It took a couple months for me to figure out, some people get so frustrated that they sell the car. It's a phantom that you can chase deeper and deeper into the engine that will cost you time and money. The FSM won't help very much either. You should spend a long time observing before you replace anything. I strongly advise you to reinstall your factory intake while attempting to troubleshoot this DTC

What's important to understand is that these codes are triggered by the ECU. There very well may be nothing wrong with the actual sensors or your fuel system components. P2A's are thrown when the ECU is confused about the data it is getting back from one or both of your Upstream sensors. It's diagnosis logic for this is very simple and can be tripped by unrelated events. The A/F sensor voltages you see on a scanner are the product of an internal calculation undertaken by the ECU in which it references the amount of current it is supplying to the sensor against frame ground voltage they are not a direct output.

I had both codes appearing on me after just a couple drives. It turns out that It was the transmission, seems that it will get stuck in 4th intermittently after the car has been held at running temp for a while. It was causing a very sudden rich condition during city driving, getting stuck in a high gear at low RPM was enough to do it. Right now I've been shifting manually for ~400 miles and they haven't come back. If you are getting both codes and not just one it is a clue that the problem is systematic.

 

I can give specific advice if anyone needs help.

 

I'm at 2000mi now and P2A has not shown back up. A/F and o2 sensor voltages are stable on both banks. After cat o2 sensors should fluctuate around .68v with a 1v max.

 

Hello Velix.

I am having trouble with P2A00!

I've replaced
-Bank 1 Sensor 1
-Replaced 2 hoses
-Sealed up a crack plenum spacer
-Borrowed a friends catalytic converter and replaced it but code came back!

I posted a thread in case you want to read it:
https://g35driver.com/forums/g35-cou...ml#post7082796

 

I have both codes and have replaced the sensors already
p2a00
and p2a03

i have art pipes with fast intentions exhaust and 5/16 soacer
i have tightened my plenum bolts and have cleaned my intake and re installed
i cant hear or see any leaks to cause these sensors to go off

what else can I check? I honestly thing if I go back to stock cats it will erase the codes

 

Did you run the self-learning process? It takes 15 minutes and it's free.

http://infinitihelp.com/diy/gcoupe/p...f_learning.php

 

Anyone find a solution? I have had my tuner check for leaks, cleaned MAF, replaced Bank 1 Senor 1 (I only am throwing P2A00), done throttle relearn procedure and SES still comes on every 100-700 miles. Mods are below. I am at a loss for what it could be at this point.

06 6MT <40,000 miles as of this post
MD 5/16 spacer
MREV2
Z-tube
Berk HFC
HKS catback exhaust
Uprev Dyno Tune after all parts installed

 

Sounds like a mixture ratio algorithm learning error hence why it takes a while for the problem to manifest. I would still take a hard look at (or just replace) the bank1 fuel damper just to rule it out but you might be a little rich at some point in the fuel map too and it eventually throws the computer off because it's expecting a different value.

Clean all your grounds just in case something has a little resistance, there are 4 lugs, battery to chassis and then the chassis to engine (under the coolant reservoir).

I think you can reset the algorithm manually by unplugging the MAF, getting the code thrown, then plugging it back in and erasing the code. Not totally sure but it should force the mixture learning process so you aren't always having to unplug the battery and lose temporary settings.

 

Clean MAF and ECU reset got it.

 

hello there I just happened to read your post and I would like to know if can I get some help from you because am about to junk my ride I swear...hope to hear from you very soon thanks in advance.

 

What's the car doing and what codes showed up when you scanned it?

 

Fixed!