ok so while driving into town today the CEL popped up, i heard no changes in engine tone, nor did the engine feel different(didn't try to build any real boost tho, for safety). everything seems fine, and i would get the car into a autozone to check/clear the code but we have no autozone here, im going to call napa and see if they have an obd2 reader. i was pretty low on gas when the code started and have been for a while of driving and only putting in minimal gas(its really expensive where i live, but not 15 miles out of town), so im thinking it may be a lean condition caused by not getting full gas pressure due to the low tank.


well anyways the real question(guess it wasn't that quick) is will the CEL light clear itself as other vehicles do? after some number of miles or successful drives? if someone knows the EXACT number of miles or trips it takes to reset the CEL please le me know, thanks.

 

I serously doubt your CEL was triggered by low levels of gas in the tank. A CEL can be triggered with absolutly no noticable change to the driver. The i'm not exactly sure how long it takes for the light to go out, i've run one for several weeks, then it finally extinguished. Your's may never go out, if there is a constant problem. You should really consider investing in a Vag-Com cable.

 

yeah i checked out the vag com, bit pricy for my tastes(hell everything is), so im researching other alternatives. i will look for a place to get the codes pulled and cleared. i mentioned that i didn't notice any change since if a sensor, or other device faild suddenly the engine would most likely let me know thorugh vibes and sounds, which it didn't so i feel its not major.

if the audi system is like most other modern cars then running on empty could definently cause an engine CEL. you see what happens is when there is just a low level of fuel in the tank and you run over bumps or even just normal road(come to think of it the road i was on was bumpy), the fuel splashes around. only when there is not much fuel in the tank the splashes can allow air to get sucked into the fuel pump, the air in term travels throught the fuel lines as fuel is pushed in behind it, it blends with the fuel or creates a bubble. when this air fuel mix(at the wrong point) reaches the injectors the injectors open and close their predetermined pulse length, regaurdless of wether its air or fuel or both, if your not injecting the correct amount of fuel with the correct amount of air what do you get?? yup, a lean condition. the primary o2 sensor changes its voltage output and the ecu interprits this as a lean condition. depending on duration and sevarity of the lean condition this may cause the ecu to go into limp mode(low rev limit, pull timing, possibly lower boost). so unless audi is unlike most all other cars on the road i believe that running on a low tank(light constantly on, even after fueling(a little)) can indeed cause a check engine light.

does anyone else out there know how long a light will last if the problem is resolved? thanks

 

Well you can hypothesize all night if you like. The fact remains, that it could be any one of 100 codes causing you CEL.

And you can get a generic reader for 60 bucks. So really not that pricey. You can reset your CEL by disconnecting the negative battery cable for an hour or so too.

 

yeah i realize that it could be anything im just hoping im right lol gas is cheaper than parts i was gonna reset the ecu by removing the neg terminal, but since its a new car and the dealership is closed im going to lose my radio till monday as i neglected to get a code with my car to unlock the sterio security, which i assume the audi symphony thing has(**** my 92 civic did lol)

thanks for the help, i might go halves on the vag com if my bro keeps his b5 passat, then the hit won't be so bad.

 

May or may not reset the radio. Mine never resets. The code isn't in your manual??? Also It might be in the spare tire well.

 

ohh thanks for the tip, ill check the tire well. unfortunently i believe one of the previous owners kept the owners manual as a souvineer(sp?), the dealer has one on order for me but until then...

 

welcome to the euro scene my friend

 

lol so im finding out! aw well you gotta pay to play.

ill keep you guys updated on what i do, since usually whatever im doing im doing as cheap as possible.