It came on yesterday on the highway as my wife and I drove to BJ's. It's a steady light, not blinking. I went to Autozone to get the code scanned, and it turned out to be a P0456 (very small leak in the EVAP control system). Not exactly sure where the leak could be coming from, I drove over to the dealership and got the parts manager to help me out. According to him and the service dept, the problem is the gas cap not being tightened enough. He said 99% of the G35's he's seen has that problem. I've always tightened the gas cap to 4 clicks after every fill-up and have never gotten a SES light until now, but we went ahead and retightened the cap some more. He said that after about 100 start-ups, the check engine light should go away.

Should I follow along what the dealer says about the gas cap, or should I look into other possibilities like a cracked vacuum hose, vapor pressure sensor, charcoal canister, etc.? Anyone else have experience with this particular error code?

 

I had this same code on my Maxima. I would reset the ECU and it would come back after about 186 miles. It wasn't my gas cap.

I had my first SES light in my 2006 G35 (just bought it in December) at 1450 miles. Blown MAF. And so it starts... I hope this car isn't plauged with SES lights like my Maximas have been. ):

 

The only light I've had issues with is the Tire Pressure monitor light.

Either very cold mornings, or long distances when temperatures are near 100, can set it off.

 

I never had that problem until I started doing a lot of mods. I have heard about the gas cap problem but it's not on 99% of G's. Maybe 5-10%.

 

I have about 50 k on mine but no SES lights...I hope it's not faulty. I have the tire pressure issue though. I check the tire pressure everytime I make a long just in case it's low but the light still comes on...

 

I had the same thing happen to me in December. After driving around for about 45 mins on the highway, the light disappeared.

 

Same here around Christmas and I have 25K but it went away the next day.

 

Just reset your computer and see if it comes back on. If it does, then take it to the dealer. If it doesn't, then you saved yourself a bunch of grief.

 

how can i reset the ecu?

 

Pedal method, do a search. Disconnect negative battery cable for 8 hours, overnight.

 

OK, I did the pedal method (link HERE) and the fuse pull method (link HERE), and my SES light still stays on after start-up. I haven't done the battery disconnect method yet but I'm pretty sure that won't clear the SES light. This leads me to believe there is a leak somewhere in the EVAP control system (and by no means do I want to shell out $$$ to the dealer for something like this)

 

Sounds all too familiar...My vehicle failed Inspection (NJ) cause of the Gas Cap but no light ever went off. Dude at the Station suggested I go to AutoZone and buy a cap. Problem solved. Now, as for the Tire Pressure Monitor light, that's just irritating. It goes off every time during long distance drive. I contemplating taking it to the dealership since it's still under warranty.

 

yea, my tpms goes off after long drives too....I dont know why



also, after filling up my gas tank, my SES light turned on for the first time. my first thoughts were

A) about three weeks ago I installed Plenum, HF Cats
B) it was FRIGID outside, maybe a vacuum hose cracked or what not
C) maybe I overworked my transer case in the snowfall

a few days later I realized that due to the cold, the gas cap is RIDICULOUSLY difficult to tighten...this maybe due to my hands which turn into solid chunks of ice in such temperatures


so I have not reset'd my ecu or what not - local mechanics want 60 bucks to check the computer

so I am just going to assume that since
A) the additions to the vehicle did not give me problems before
B) the SES light came on about 30 seconds after I left the gas station
and
C) the car runs perfectely fine except for those usual cold weather rattles

that it must be due to the gas cap

 

I removed the connection on the neg terminal for a good half hour and after a full day of driving the SES remained off. pheeeeeeeeeeew!

I guess it was just the gas cap than

 

I read the manual when i got a service engine light. I was freaked out because it was christmas time and i didn't want another expense for the holidays. It said that the gas cap needed to be tightened. After a few start ups and a few miles the light went off in like a day. good luck