DigitalWidgets

2011 GS A6 with 107K miles on it.

About a month ago, I let the gas tank run pretty low (just wanted to get home from work) and that's when the problems started. After filling back up, all was fine for about a minute, and then I hear the warning "bing" and the fuel level goes to 0 and "LOW FUEL" warning comes on....then SERVICE FUEL SYSTEM/LOW FUEL, etc. 2 minutes later, all goes back to normal. Then LOW FUEL warning and fuel gauge is reading a full tank, then empty, then 1/2 tank. OK...I get it. It's confused about the fuel system.

Since I had a full tank of gas, I figured I'd just give it a day or two to sort itself out. And it did...till next fill up and then same symptoms. The car was running fine and I had an autocross event, so I figured I'd just put it off till the next week and keep the tank full.

Then while cruising down the freeway, I get a few more fuel warnings...and then bing bing...and just about every warning I think the DIC can display: MAXIMUM SPEED 80, SERVICE ACTIVE HANDLING, SERVICE ABS SYSTEM, SERVICE TRACTION CONTROL, etc. Check engine light came on and the car also had significantly reduced power....I was in a divided carpool lane with no exit and I was worried about maintaining freeway speed. I limped along till I could pull over. Stopped, restarted the car and all was fine (except check engine light was still on). Zipped along back to work and by the end of the day, the check engine light was off and all was fine.

I disconnected the battery (overnight) thinking maybe just a reset may help. The same intermittent fuel warnings and 2 major (all the errors and check engine light) events happened over the next few days till I could get the car to the dealer. I purposely did not disconnect the battery in hope that some error codes would be in the ODB2 system.

At the dealer, I explained the symptoms, and asked for the fuel smell recall to be done at the same time (hoping it would save some money since they had to drop the tanks for that). The dealer came back with $800 in charges to replace the fuel level sensors (and the recall had the fuel pumps replaced I guess). They also told me there were no error codes in the system, and they were unable to recreate the other issue.

So...now I've got the car back....and I just filled the tank (over 14 gallons till auto shutoff)....and the fuel gauge shows half a tank. I have had it back 4 days and so far the other symptoms have not re-occurred.

So I'm looking for some thoughts from the forum. I'm hesitant to return the car to the dealer for two reasons:

1. The dealer assured me that they had the car out on a long test drive to recreate the problem. A 10 mile loop he said. Interesting that my odometer showed only 2 miles difference from when I dropped it off. I don't appreciate BS stories if you can't recreate the problem. In reality, they put in the absolute minimum of effort in recreating the problem...what they drove it around the block?
2. And this one frosts me: I changed my tires from my autocross set to a scrub set of street tires over the weekend. The rear lug nuts were torqued so tight that my electric impact wrench did nothing after hammering away 15-20 seconds. I had to stand on the end of my breaker bar to get them loose. I swap the wheels on my car a couple of times a month, and I know what 100ft/lbs. feels like...it's not all that tight. This was obviously letting their shop impact wrench hammer away for a bit. Is it really that hard to properly torque the lugs when replacing the wheels? I question the professionalism of any mechanic that does foolish stuff like that.

So, sorry for the long post, but I'm looking for ideas and any potential things I can try to just get the issues resolved (both the fuel system and/or the electrical gremlins) before wasting time returning to the dealer. Any thoughts or ideas would be greatly appreciated.

TIA!

extrapilot

Sounds like you have or had network communication issues, with all the DIC's alarming. The dealer would be wise to check all the related connectors to the modules, along with a good load test of the battery. The fuel sensor issue could be separate, but with your previous issues, there maybe nothing wrong with them.

AORoads

As said above there could be something else wrong with the car like a gas pedal sensor (which causes all the lights on the dash to come on and go into limp mode but throws a code). And the dealer couldn't, or wouldn't do all that it can w/o your permission: remember that all your issues start with an empty tank. By the time you took it to the dealer it wasn't empty. That doesn't mean a great job, it just means they didn't replicate your original causation. At $800 and no complete solution, I'd replicate the near-empty tank, and take it to them and ask to go with the tech who fills it up. Or, if you have an indie shop nearby who knows Corvettes, that might be another route to go.

Warship2k15

Check the ground wires.
if its loose it will do all kinds of things.
And its cheap to fix.

if they are all good then as someone said do a load test of the battery AND charging system.
Also how old is the battery?
I have seen wierd problems if it was old even when it checked good.
The shaking, heat and movement would cause a shorted cell.

I would start with those because they are the basics ,are relatively easy to fix and don't cost a lot.

Nothing like shelling out loads of money to fix a problem and then finding out it was something simple and cheap.

extrapilot

So true.....

DigitalWidgets

Thank you all for the thoughts and advise so far. As luck would have it, I drove the car to get a bagel with the wife this morning and suddenly got a CHECK COOLANT LEVEL warning. I was a bit skeptical with all the other warnings...but soon the temp gauge started to rise.

So...now I've got a major leak at the top driver's side radiator (either the radiator or the hose). I stopped and refilled the reservoir with distilled water and dropped the car at my local trusted non-dealer mechanic. He's good (and honest) for the basics, but not a Corvette or performance shop by any means.

So, now I'm on hold for some of the ideas mentioned till he let's me know if it's the radiator, a hose or what.

Replacing the battery is an interesting idea. I've had several electrical issues over the past year, and nothing definitive has ever been found. I've been using PepBoys batteries for a number of years because they keep failing and PepBoys has been great about free replacements. That being said, they've been failing well within their two year warranties for a few batteries now, so maybe some of this is something to do with battery. At one point, one of the DIC message was BATTERY VOLTAGE TOO HIGH and the volt meter in the dash did go up to the top for a bit. Of course, I don't know if that's a true analog gauge and the battery voltage did actually spike or it's an analog gauge based on some digital sensor that was having an issue.

Anyway, the battery seems to be an easy/cheap thing to try first.

extrapilot

This is why LOAD testing is important, as it will simulate the starter load and will show the actual strength in amperage at that point.

dpigguy

Also check all the relays in the passenger footwell to ensure they are seated correctly. Have seen some strange warnings arise from a loose connection.

CadVette

Two things seem obvious. Number one is you should not return your car to that dealer. Two, why would you put an inferior battery in your car again since you are familiar with Pep Boys quality? Yes they may have a good return policy but is it worth the risk of problems like this or leaving you stranded every two years? Beyond this check your electrical connections at the PCM. Sometimes corrosion gets in the pin connections.

CSixDude

I'd put a bottle of Chevron Techron fuel cleaner in the gas tank. It can help remove sulfates off of the fuel level sending unit, which it sounds like what is causing your gas gauge issues.

Terry Aspatore

This remedy solves most electrical warnings. It's happened to me twice and both times it had to do with the fact that the passenger put very hard pressure in the foot well. To save weight, the manufacture used light weight wood, balsa? in the foot wells. Undo pressure sometimes causes the connectors under the floor board to loosen and the computer system sends out the warnings.

Terry