Hi guys, in a former occasion my service light went off, I bought an OBD2 diagnostic tool and hooked up to OBD computer's car I don't remember the code number display showed but it was "tighten up fill cap" I checked my gas tank cap and was rusted not the cap but the pipe, I sand it and oil it, close the cap and tight, hooked the tool and erased the code...everything went just fine until today (that problem happened last December) light went on again, hooked the scanning tool and...NO CODES just "error" I ran the test 4 times and always the same...please help I can't erase the code I'm assuming is the same problem with gas cap. Thanks beforehand.

Use a different code reader


post up the code number. If it's P0455 that usually the universal "tighten gas cap" code, but on the G35 it tends to be the EVAP valve on the charcoal canister in the rear bumper. This is why the code NUMBER is more important than whatever the scanner reads.

I recently bought an '05 coupe and while doing some repairs disconnected the battery and later the service engine light went on. I then disconnected and reconnected the battery again and it went out. Go figure.


Also, don't get an emissions test immediately after disconnecting the battery. I did that and it failed and the guy told me to simply run it for about a week to let all the little gremlins in brain box get arranged correctly. Took it back a week later and it sailed right through the test.

I had the same issue and it only happened in the summer intermittently. I replaced the gas cap and sanded the fuel filler neck area. It was gone for about a year but it returned last month when it was raining.

Last week, I had the car at the delearship for warranty work and it looks like they cleaned the gas cap area and the code is gone. Maybe they erased the code or it went away on its own.

thank you guys for your comments, I'm gonna clean the fill cap before going to stealership to get a new one, and see if light shuts off by itself

This all started happening after I took my car in for a simple oil change. Cheaper for them to do it since I had coupons. Engine light came on after leaving and my car felt sluggish like it was stuck in 3rd of 4th gear, automatic 06 g sedan. my manual mode isnt working either and shifts hard when switching from neutral, park, reverse. Plz help

What's the code number?

Without that we are just throwing darts at a board

p1757, also If i bought a used transmission will it already have the a/t front brake solenoid valve?