SteveC6R

I got the Service Fuel System message in the DIC and the gas gauge is showing empty. I have read that this was a problem on the C5 and early C6's but don't know if this issue was fixed or not. Mine is a '07 with 2300 miles when it happened. I know it was the Fuel Sending Unit but the thread in C6 FAQ is from 2005.

The bigger question I have, is there a list of things to check to see if I can get it back working before I take it to the dealer?

DaveC6

I had the same problem. Pulled the battery and that was a temp fix. Then I used an HP Tuner to clear the codes. But none of this kept it from reoccurring. This sounds exactly like my problem. It is caused by corrosion of one of the sending units and it occurrd when I got to 1/3 tank each time. I did not want to take it to the dealer so here's how I solved the problem.

First I put in a bottle of Techron concentrate. Then I filled up with Shell 91, a Top Tier gas. I used to run only Mobil when this occurred after 6,000 miles. I thought Mobil was a top tier, but it's not. Then I never let it get much lower than 1/2 tank for a few weeks. Then one day I decided to test it and it ran to E without a problem. I bet I did not need to go that long, but I wanted to try to clean the sensors and didn't have time to fool around with pulling the battery every tank. Now I'm only using top tier gas, which is Chevron or Shell where I'm located.

LS WON

I got this reading "Service Fuel System" at 96,000+ miles on 2005. Some times the engine light will come on and stay on. I did do the Chevron Techron treatment a few times with no success and still have the very same problem. I am curious when that "Check Engine Light" stays on will this make the car not pass the smog test when that light is on?

C5 Diag

You will not pass your state emission with the check engine light on…if you take your car to your friendly auto parts store they should be able to tell you what code is turning the light on with their scan tool.

LS WON

I guess I am better off when the light is not on because it doesn't always come on (Check Engine light) when fuel guage acts up.

hubes

It's most likely caused by a bad fuel sending unit. Some people have had luck with a couple bottles of techron, some people have had to change the sending unit

LS WON

I know. I just want to pass the smog test when the "Check Engine" light is off.

LS WON

What the cost of having the "Service fuel " system which has the check engine light on?