Bought a 2000C5 convertible in 2018 with 29000mi. Had all the electrical quirks. ABS/TCS, TBS, AIR CONDITIONING, TAC, REDUCE POWER. You name it my car had it. Fought the issues for several thousand miles. I have replaced a few parts but nothing major. What I did do is the following: Replaced battery. cleaned TB, cleaned MAF, replaced TB sensor, cleaned all grounds. Periodically activate ABS/TCS. I now have 43k pleasure miles. on the car and the only issue I have left is the gas gage goes to empty. It went to empty with 3/4 of a tank. However, the guage issue is intermittent and clears when I clear the DIC error code. I am going to clean the ground again to see if that helps. The car is a real pleasure to drive now that I fixed the issues. You don't have to be a corvette mechanic to do what I did.

 

Sounds like sulfur buildup from the fuel. Try a bottle of Techron with each fill up and see if the issue goes away.

 

Wow !!…a couple of these gas gauge issues here within the last 24 hours…first scan for codes if you know how through the DIC…second run non ethanol fuel if you can if it’s available in your neck of the woods…get some Techron or BG44K and add it to the tank when it gets down to a 1/4 tank…that way it goes into BOTH tanks…you may have to do this a few times…there is a TSB issued in 2003 which addresses this issue and a PCM “recalibration” is required…I would do this as a last resort…good luck !!…moving this to Tech !!

 

Nice looking C5.

I'm getting the ABS/TCS codes whenever I hit a decent expansion crack. Codes always point to the left/front wheel. I replaced the wheel hub assembly but it didn't fix the issue. Where might I find the ground for that particular area?

 

Lovely convertible. I bought an '01 convertible four years ago with 96,000 miles on it. Your experience serves as a cautionary tale for those who insist that low miles is an absolute guarantee. You've done a great job making your car a better car than you bought and that can be a great source of satisfaction.

My '01 has had only 3 of what I would consider electrical issues in the last 4 years and 20,000 miles- the "pull key wait 10 seconds" (my car a manual)- which I took care of with the installation of the LMC5; the gas gauge issue- which might be different than yours- because a few bottles of Techron and using nothing but top tier gasolines cleared that up almost immediately (if you have not tried that already, you might wish to...a near magical solution to a very common problem), and my under hood light- which works sometimes and sometimes not (I suspect a bad mercury switch- but because I don't care if it works- it is a non-issue).

Even some of my mechanical issues, which you may face sooner or later with your low miles car, you don't have to be a mechanic to DIY thanks to lots of good videos and advice on this forum- other than the LMC5 install, I have replaced a front indicator bulb, visors, serpentine belt, idler pulley, water pump and rear sway bar end links on my car. Probably saved over a thousand dollars in labor.

 

PLEASE start a new thread with your issue !!…thanks !!

 

Fuel gauge issues are a VERY common issue with the C5 fuel system. The sensors (one in each tank) are prone to oxidation that causes the gauge to go crazy and often drop to empty (the default gauge level). Because there are 2 tanks on the C5 and one sensor in each tank, the computer calculates the amount of gas left in the car to display on the gauge. Further since the passenger side tank is emptied first the computer expects to see the level in the passenger tank decrease BEFORE the level in the driver’s side tank. If that does not happen because oxidation on one or both of the fuel level sensors, there are one or more PCM codes set.

If you pull and post your codes you can determine which of the
sensor(s) are experiencing the problem. You can also treat the fuel to attempt to dissolve the oxidation to avoid future gauge issues. Get yourself a couple of large bottles of Techron Concentrate Plus from a parts store (20oz bottles). With the tanks down to 1/3 of a tank (2/3rd's empty) add the entire 20 oz bottle and then fill the tanks with your favorite prem fuel. Since the driver’s side tank is filled first the churn of gas added mixes the Techron and fuel and once the drivers tank is filled the mixed fuel flows over the crossover tube to the passenger tank insuring that the fuel and additive reach both tanks. It often takes more than one treatment to dissolve the oxidation. If you can let the car sit for a few days the additive will have a better chance to do its job.

If the treatments do not cure the problem then you are looking at replacement of the offending sensor(s). If your car has an early build date (before Late October 2002) you will have the old style fuel tanks and replacing the sensors is pretty easy as there are access panels on the bottom back side of the fuel tanks that provide access to the pump and sensors. If your car has a late 2002 build date or a 2003 build date the car will have the FFS fuel tank system.. Replacing the sensors in the FFS system is a BIG job as the tanks must be dropped to gain access to the pump and sensors.........

The sulfur build up can cause bad input to the computer and the gas gauge then "defaults" to zero. A turn off and restart restores things. GM came up with a PCM update (reflash) way back when which fixes the problem. It used to happen to me all the time before the reflash was done; tried different gasolines, Techron, etc., but only the update fixed it - and permanently.

It's been a long time (at least 10 years) since mine was done, but a Google search should find the info for you.

SeaFoam is another additive that folks have had success with

Also use Shell V power gas.

Can take multiple treatments to correct.

 

Thanks for the tips.
This is my 4th summer with the car. I began treating the fuel with Techron the first summer. Then I read that if you fill the tank and add the Techron you are only treating one tank. So I waited until one tank was almost empty and dumped some Techron in it. I still have the issue but when it happens I clear the codes and the gage works fine. I am going to do the add Techron at 1/2 tank again to see if it clears the problem. Prior to this the gage would go to empty and stay there until I filled the tank. I am also going to clean the fuel tank ground again and check the wire connections on the tank. The car was a one owner and only driven approx. 1500 miles a year. And I think it sat for a couple of years. The air cleaner was the original and it looked like it had 20 years of dirt in it. The throttle body sensor was bad. The MAFS was black inside and so was the Thtottle Body. All of the recalls were done on the car by the 1st owner. I also may have the local GM Vett mechanic reflash the computer. But except for the fuel gage issue the car is running great.