GGGGGWhip

so i bought my 08 g37 used in january.. the 2nd day i got it a SES light came on... and this is the code... i dunno why my friend cleared it, but he did... soo the dealership couldnt troubleshoot anything if the code wasnt there.... the light stayed off and my warranty JUST expired.... now the lights back on and im stuck with it... the car was bone stock... ever since then, i did a catback , CAI, and HFC and uprev tune.. codes still on...... i wanted to do the headers soo i figured that 2 new sensors in my stillen headers installed would fix the problem... nopee!!! lights back on!! today i sprayed both MAF sensors with MAF cleaner and swapped sensors on each inlet tube..... cleared the code..... but one thing i noticed was that my bank 2s fuel trim was considerably higher then the bank 1s.. shouldnt they be in the same area???.

NO exhaust leaks and the cai is clamped together tight.. i just dont get it???

i did a bunch of searches for this and i hate when people post a problem but never say what the problem was!!

Staples

iTrader: (9)

"O2 Sensor Circuit Range/Performance Bank 2 Sensor 1"


Could be a faulty 02 sensor in one of the high flow cats. If you want to try the cheapest way to see if this is the issue then get some non-foulers (the ones Berk provide still cause check engine lights), clear the code and drive it for a week. If this was an issue with a sensor in the header then your car would be running like ***.

The second set of sensors in the cats are for emission purposes.

GGGGGWhip

That would be correct if that's what this code was for... Bank 2 sensor 1 is the sensor in the header, not the cat

Paul58

Newbie here. I saw your P2a03 issue and registered as i just went through the whole process of dealing with this code on an M35.

P2a00 and P2a03 while legitimate codes are more or less generic for the ECM knowing there is an issue on a bank but really doesn't know why.
The whole testing of wires for messages on advanced scan tools like "open or short to battery" give this away, it just doesn't know the source of the code.

There is a brace that goes from the left cat to the right cat held with 14mm nuts and 2 14mm head bolts fastening it in the middle to the drive train.
When removing the nut on the left side (bank 2) it can tear a very small crack in the bracket lower weld where the brace attaches.
This is sometimes not noticeable. put the car on a lift or ramps let it cool and have someone start the car while you feel for a small puff at this bracket.
This may only leak slightly when the car hits a small bump in the road so wear gloves and pull down on it a little, it may not appear at first inspection.
If there is a leak it can be welded with no problem as it is a thin tear of about 1/2 an inch long not rot.

This leak gives false readings to the sensor 2 bank 2 and the ECM tries to compensate by slightly increasing injector pulse driving the bank rich.
With a enhanced scan tool you can look at bank 2 sensor 2 output voltage, if its higher than bank one it is a good indicator this is where the issue lies.

I don't usually post on forums but i thought this may help, i wish someone would have told me about this after 2 weeks of chasing a ghost.

I am a master tech with 38 yrs experience and L1 certified

Black Betty

iTrader: (60)

Thanks a million for registering here just to help out with this issue. Please stick around, you seem like a great knowledge resource that we could certainly use around here. Kudos sir!

*ICE*

iTrader: (8)

just got my P2A03 problem fixed after 3 months of it keep coming on every 30 miles. My car is running test pipes, and turned out, there was a small crack near the left O2 sensor on the test pipe, causing weird result of Air & Fuel.

Had it welded for $25 and been fine with no code for the past 100 miles!

PongSanity

iTrader: (5)

I get both p2a00 and p2a03 ever so often I chalked it up to my sensors going out so I was ready to get two oem o2 sensors. I'm on f.i. hfc. Now it seems like I should get under my car and inspect my welds. I'm not running any cat brace either. Kinda can't since there's no support for our on the hfc.

nelledge

Check out this Rochester thread with a brace solution he and his mechanic implemented.

PongSanity

iTrader: (5)

Idc to put my brace bk on actually. Because weight reduction.