my light came on this afternoon while idling in the driveway for a minute or so, so i took it to autozone to get the code and it came up p2a03. the printout reads like this:

Definition
air fuel ratio (AF) sensor 2 circuit range/performance
Probable cause
1. Intake Air Leaks
2. Fuel system fault
3. Faulty AF sensor heater circuit
4. Faulty AF sensor

Before this code came up, i use to have another code that would cause the SES light to come on every two hundred miles or so then it would go back off by itself after about 50 miles or so. i don't remember the actual code but it was similar to this one but it listed the maf sensor as well as the af sensor and the reason had to do with it taking to long to be able to read one of the sensors.

anyway, i was just hoping someone might have some more detailed info on what to look at in the engine bay. maybe point out where the af sensor and af sensor heater circuit or located.

its a 5at c and the only engine mods are k&n, z tube, hfc's with hks full exhaust and anti foulers on the O2's.

 

Personally I've never had this code come up. However I do side work as a mechanic I find that "most" of the time its just the sensor. I say if its cheap to replace then just do it and remember to reset the light. If that doesn't work then just go see a mechnic. Avoid the dealership if you can.

 

Have you tried to clean the MAF? Since you have a K&N it's possible the MAF has a small amount of oil buildup on it. You can get a can of CNC MAF cleaner at the local auto parts store for ~ $5.

Try that to see if if helps.

 

i just got the k&n not too long ago, the other code was coming up before i got it, but i will take it out the maf and look at it. anyone know where those a/f sensors are located?

 

nobody???

 

i had this problem took the k&n out sprayed maf and have not had a problem since kept stock air filter blue dream is right try it any auto parts store has spray GL

 

ok guys, its been since May that ive been riding around with the SES light still on. so just to update a little bit. before i was getting this p2a03 code, i was getting a light for a p0133 which reads like this:

Definition: fuel air (AF) sensor 1 circuit slow response

Probable cause:
1. Lean A/F ratio - fuel system faulty
2. Large vacuum leak on engine
3. Faulty MAF sensor
4. Faulty AF sensor

the ses light would come and go every 100-200 miles or so. im guessing since it was for a slow response, that when it did respond, the light would go back off for a while.

for the past few months now the light has been on constantly with the p2a03 code which is stated for AF sensor 2 circuit. i guess now instead of a slow response, it quit responding all together.

ive cleaned and reoiled my K&N and reset the ecu..... ses light came back on after 40mi.
i then removed the maf sensor from one of my others g35's and installed it in my DD and reset the ecu. the ses light came on after about 50mi. so, its not a dirty airfilter or malfunctioning maf sensor. what other sensors could i look for? is there an air/fuel ratio sensor? if anyone can help me figure out what to do next, i would appreciate any ideas. i just dont want to have to take it to the dealer unless its absolutely necessary.

 

I just got this code. The sensor was replaced about 10k ago so I really doubt that is the issue. Anyone have a solution?

 

i had this code on for months and i had a small leak in my cat and when i replaced my cat the light shut off after i drove for like 80 miles.. see if there is any sort of exhaust leak

also try cleaning your MAF SENSOR