i would just take it to pepboys/autozone or wherever. almost all places will read a code for free.

but if you have aftermarket cats and exhaust then it could have been caused by that. doubt hid's would cause a service light, the timing may have just been coincidental

 

ha ha - I just had my ECM replaced for the whine, and started getting this light 2 days after; I find it funny that the last step in the diagnostic procedure is to 'replace the ECM' - so the new ECM must be a little different, or have a different flash for the tune, and is essentially incorrectly triggering an air flow sensor issue/problem. if I read all of that correctly, plus the rest of the thread. If you have never had your 2009 G37 ECM replaced, than it could indicate a real issue, but if you had, it seems that it is likely a sensor-to-ECM conflict with the new ECM. So, if this is the case, then why not blame the sensors? Did the sensors change in the 2010s and are not conflicting with the new ECM model? It's all so aggravating.

 

So my stock 09 sedan got the "Service engine soon" light last night. I can't take it to the dealer today because it's Sunday, so I have it checked out at the local autozone. Code is P0456 "very small leak in the evap control system".

I actually tried to tighten the fuel cap but no luck. Will take it in tomorrow and let you guys know.

 

I got the dealer to check the car 3 times over till they finally replaced the gas cap with a new one and so far (knock on wood) its been working fine!

 

Update: after a couple of trips after I tightened the gas cap, the light reset itself last night. I'll probably bring it up at the next service.

 

Could this be caused by overfilling your gas tank? I've read that you shouldn't continue to try and top off the tank after the pump clicks off on any newer model vehicle.
I think what happens is, if you fill the tank up until the gas comes up to the top of the filler neck, some gas will flow into your vent tube. Continually doing this will cause damage to your system.

 

1)
Had the P1421 error last year.

Tried tightening gas cap and it still occurred.

My mechanic traced through everything, and it turns out that an EVAP connector/wire was loose in the engine bay. I don't remember which one, but as soon as you pop the hood and remove the engine cover, you can see it.

The error code was gone as soon as that wire was clipped on again.
Might or might not be your solution, but worth a shot.



2)
Another issue that came up a month ago was that it couldn't read the a O2 sensor. (forgot which error code it was, but it said something about O2, left bank) Infiniti jacked up the car and noticed that one of the wires leading into a connector to the O2 sensor had been spliced or had corroded, so the signal wasn't going through to the sensor.

Infiniti's suggestion was to replace the entire wiring harness (to guarantee that the wires won't corrode again), which would have involved dropping the transmission to get to the wires...their quote was around $1500 of labour (5hrs) and parts (new wiring harness). They said it wasn't covered under warranty b/c the wire "appeared" to have been spliced, and they don't cover corrosion in the wire... WTF?! (my car is 100% stock)

My mechanic was able to find an identical connector from another Nissan, and he attached the existing wires to the new connector, and clipped it back into place. Problem solved for $100 of labour (1hr) and parts (used connector).


Hope this helps.

 

what I dont get is, why would Infiniti make a engine code when they dont even have a fix for it. I have spoken to management at a couple dealerships and they assured my Infiniti is working on a fix. This is a rare problem yet annoying cause I have to stare at this light everytime.


thanks for the tips rusty, will check the engine tomorrow (but I am complete stock engine wise so we will see)

 

HELP. Im having the same problem after having my ECM replaced for the "whine" noise. 23710-JU60c is the ecm #. my check engine code is P1421.. anyone figure this out?

 

sounds good!

 

My fix was the "Idle Air Volume Learning"

 

I started having this problem right after my Uprev Tune