Persistent TPMS Warnings Solved By A Dealer Reset?

[Equinox]

Hi All!

Just got my 2016 Leon FR 1.4 EcoTsi back from my local dealer after I was suffering a repeated TPMS light illuminating every 40 - 50 miles or so. The dealer says they've cured it. All done under Seat warranty.

History: Bought vehicle as an Approved Used car from a Seat dealer in December. In January I started noticing TPMS warnings coming up. Every time the light came on I checked all pressures with my shiny new digital tyre pressure gauge and all wheels were equal. I would reset the warning system via the infotainment screen and off I would drive for another 40 - 50 miles or so and it would come back on. System always moaning about either the rear nearside or offside tyre.

What the Dealer Says: Vehicle required specific Dealer Diagnostic Reset to get its knickers out of a twist. TPMS module was incorrectly reporting an imbalance that would not go away with the Driver Reset via the infotainment screen. Only a 'laptop' reset using the dealer software would make it go away and to clear the TPMS memory.

Anyone else came across this? I was wondering if a large imbalance incident (like a complete flat) requires a subsequent dealer reset while smaller imbalances (like a slow puncture) can be simply reset by the driver. Is my grand theory rhubarb or what? Or is there a bug in the software that stops the driver reset from working properly?

Warm regards,
Ivor

 

[BoomerBoom]

To my knowledge the TPMS system relies wholly on the ABS sensors to detect differences in wheel rotational speed, hence the diameter of the tyre and so it's inflation status.

If a sensor was faulty the ABS/ESP would quit so it's possible the software for the TPMS had a glitch and just needed 'turning off and back on again', something difficult to do without resetting the ECU I'd guess.

 

[Equinox]

Thanks BoomerBoom, indeed I understand that the Leon uses an "indirect" TPMS method which is a low-cost system all done in software using the existing ABS sensors on the wheels. Any fault with an actual ABS sensor itself would light the dash up like a Christmas tree as it would throw out the ABS and traction control as well as the TPMS.

So it's this idea/suggestion of a 'glitch' or 'quasi-dimensional flurry in the space-time continuum' which I'm most interested in. Why some low inflation reporting by the TPMS system can be easily cleared by the Driver Reset whilst other low inflation reporting can only be cleared by a trip to the dealer.

 

[BoomerBoom]

I think you'll have as much joy trying to work out why the network card driver in your pc, or printer connection just stops for no apparent reason but a restart gets everything just perfect again.

The driver reset just tells the ECU that the current sensor input levels are the correct ones, but if the ECU has a cache corruption then that won't help any and you can't restart the ECU.

 

[Equinox]

I think you'll have as much joy trying to work out why the network card driver in your pc, or printer connection just stops for no apparent reason but a restart gets everything just perfect again.

The driver reset just tells the ECU that the current sensor input levels are the correct ones, but if the ECU has a cache corruption then that won't help any and you can't restart the ECU.

I know what you mean LOL. Interesting comparison to our beloved computers though as I never actually tried a "restart" on the vehicle. I wonder if actually disconnecting the battery and reconnecting it would have changed anything. Cached memory would be non-volatile and may have not been affected of course. Must search for correct battery disconnect/reconnect procedure on these cars...

 

[Seriously?]

I had similar electrical nonsense recently on my car (although not a SEAT). The drivers door switch unit containing window and mirror switches plus rear window lockout packed up. Full of fears of failed expensive door control modules, I pulled all four fuses in the 2 separate fuse boxes to check them - all OK and absolutely no signs of corrosion or moisture on the fuse blades or the fuse box terminals. Plugged the fuses back in and everything worked.
Obviously the automotive equivalent of unplugging your router, waiting 5 minutes and plugging it back in.

 

[Rooster]

I know someone who had persistent TPMS warnings on his French car, which the dealer could not fix. Winter 2018 and his battery completely died, and guess what when a new battery was fitted no more warnings! He even let some air out of one tyre to check it was working!