Display on my C6 with RunFlat tires said RR tire flat - Max speed 55 mph, and showed 0 PSI. Two miles later indicator went out and PSI displayed 32 PSI. Is this normal when RunFlats go flat, or is it just a TPMS sending unit which is going bad? Put another way, how does one tell if a Run-Flat is really flat? Also, can a Run-Flat tire be repaired if you pick up a nail, etc?

 

Check the tire with a tire gauge. Sometimes the sensors can act up or the battery in the sensor is going low.

 

Run Flats can be repaired but it depends on the tire manufacturer. I had a nail in the original Goodyear run flat on my 2009. Goodyear recommends tire replacement because any repair voids the speed rating. My Michelin Pilot SS zero pressure got a nail and their policy was a plug patch and it will drop the speed rating one level. So now I can't drive 186 mph but 168 mph is what it is rated at with one repair.

 

Thanks. I've done this and it appears that it is a sensor problem.

Just out of curiousity, what will the tire guage read if the run-flat is actually flat? Can you run 55 with 0 psi? Also, can the sensor battery be replaced?

 

A tire gauge will read what ever pressure is in tire. I am not certain how low the tire sensor reading will go. Mine identified the tire position and low pressure and about 23 psi. Usually a run-flat or zero pressure tire can be run for 50 miles for 50 mph with no pressure per manufacturer's description. They are designed to run on the thick heavy side walls at zero pressure. An inspection from the inside at a tire shop will determine any cord damage and if the tire is serviceable.

The sensor battery can not be replaced because it is sealed. There are those out there that can remove the sealant and replace the battery. That is beyond my ability or desire. There are plenty of good after market sensors out there for replacement. You just have to match them with the year of your corvette for compatibility.

 

You can get erroneous DIC readings from several sources. Anything that can disrupt radio waves has that ability. It could be simple like a bad ballast in a light fixture or an older car without shielding on the ignition system. It sounds like you had a momentary RFI event as the TPS was doing an update. It does updates while driving once a minute. When dropouts of individual sensors happen, it takes 3 ignition cycles to reset. My LR sensor (the last one to send updates) has indicated all sorts of failure notices for the last 60K miles. I don't pay attention any more, since I know it'll correct itself soon.

The 55 MPH notice on the DIC is a suggested speed. There is no speed limiter tied to that notice.

Yes, you can drive on RF tires when there is no pressure. I had an alternator die with about 830 miles on the car. The DIC started lighting up with all sorts of messages. When a flat tire message appeared in the batch, I gave it no extra notice. I was about 60 miles from my destination on a rainy night. Knowing the battery had limited time regardless of speed, I drove 80-90 MPH. I arrived, pulled in the driveway, and the engine quit. The floor mounted door release was the only way out, without removing the top. After the car sat for a few hours, it fired up enough to get to Chevy dealer a couple miles away. When parking in front of the dealer's service entrance with far more light, is when I noticed the LR was flat and confirmed it with a gauge.
Since the car was only 2 weeks old, and I was 1500 miles from home, the dealer took care of it quickly.

 

If can read as low as zero if there is an actual issue.

When the battery fails you replace the whole sensor. They are not very expensive.

 

If you drive with it at zero psi for the rated distance at the rated speed the tire will be deemed non serviceable by most reputable tire shops provided you give them these details.

 

When my ZR1 reached about 3 years old, the RR TPMS sensor would every several weeks read XX at the same location on the highway to work. I am pretty sure due to an RFI source at that location overwhelming a prematurely weak RR TPMS battery. I would park at the office and most of the time, the sensor would read normal again in the afternoon when time to drive home. My 07 vert in eleven years of driving past that same location (I alternate cars to work) never once had the TPMS system misbehave. The 07 still has the OEM sensors when I sold the car a couple of months ago. At six years, Discount replace the rear tires and rear TPMS sensors on the ZR1 and have yet to re-experience a problem from the rear sensors.

 

Most punctures will still hold air pressure for a period of time and distance. Hence, I always recommend putting air pressure back in the tire and not driving on it with low or no air pressure any more than necessary so that the tire can still be repaired.