TPMS light, once, but pressures fine?

If you have a full-sized spare tire, check that too.

 

Sadly - I think a full-sized spare is only offered in your corner of the planet. Definitely not here, or USA - not sure about UK (or EU?)?

 

It is most likely glitch in the sensor signal or receiver. It is too early for battery failure. If the warning light stayed solid, ECU must have had a problem receiving the radio signal from the sensor. If it recurs, there may be some problem with one of the sensor. This is why the idiot warning system has very limited value. I am using external TPMS on my car to monitor real-time psi and temp. I can see each tire condition whither the car is on or off, parked or driving. End of story.

 

The light came on with my C. All pressures checked out. Light stayed on.

Visited dealer and asked them to hook up the scanner/computer to see which tire it thought was bad........that is an available diagnostic option, right ?

Well they ignored what I asked and just did a "retrain/reset" on it, saying that just happens sometimes.
I could have done that myself.
Grrrrrrr.

It has been a couple of weeks now and the light has not come back.

 

I have been having sporadic, very infrequent false TPMS alerts for several years on my 2012, so far no more than a handful of days per year. When it happens, it can warn a half dozen times in a cross-state trip (400 miles) (usually a hot day), then not happen again for six months. It has happened on both my summer and winter wheel sets, but mostly on the summer set with sensors (and batteries) a couple years newer than the factory set.

Once it started, I took advantage of ScanGauge's brief free firmware upgrade offer to display the TPMS pressures and temperatures. This reveals that the episodes are driven by a single sensor getting missed, going too long without an updated reading. Sometimes no reading is received soon enough after startup, so the display reads -14.5 psi instead of +38-ish. Other times, it holds the last value read, and I can see that one remaining fixed while the other three change with temperature.

In all cases, the car eventually gets a good reading and the warning light extinguishes. But if it happens once on any given day, it is likely to repeat later the same day on long trips.

No proper solution yet.

Prior to these episodes, I had a couple instances of valid TPMS alerts on low tires, once with a fairly rapid deflation. So I can't ignore them, thus keep one ScanGauge field fixed to the TPMS gauges to check out the symptoms.

 

In most of my events, possibly even all of them, my phone was neither recharging nor had an active data connection, only a voice-text connection. But since mine is a different generation than yours, those sorts of details would likely have different hardware.

Gen2 receiver location: TPMS antenna and receiver location? | PriusChat
I'm not finding Gen3 and Gen4 locations at the moment.

 

I wonder if you were to re-initialise the system if it would help?

Now I'm home - I've copied the other few pages - not sure if it's any help.

 

If it is always the SAME single sensor failing to report......the solution should be obvious.

 

Techstream is useful you can see the data. Hard to say what is going here, but maybe one TPMS has an internittent reading.

The way it works (on Gen2) it gets a new pressure reading from the TPMS about every 60 secs or so. If the TPMS fails, and stops providing new data, it keeps the old data for potentially weeks if you do short trips. If you finally do an approx. 30 minute trip, the system does a check to realizie it is not getting new data and the light goes on.

 

My Gen3 has shown the warning much sooner than 30 minutes after startup. But I won't project that timing to other generations.

I haven't tracked the warnings through wheel rotations (incidents are very sparse), so don't yet know if it is the particular sensor, or the particular wheel location with respect to the receiver.

But I did note that the first episode with each wheel set, summer and winter (separate wheel/sensor sets, so obviously different sensors), occurred within a month of each other, straddling a seasonal tire swap, before I had the ScanGauge firmware update. The normal interval between episodes since then has been much longer than that.