ND1 Miata, TPMS issues?

According to The Bible NDs didn't have TPMS sensors mounted in the wheels till mid-2018.  What is "mid-2018"? 

I ask because the wheels that came with my car didn't have sensors, then I hit that debris in the road and got helped out with a set of ND2 wheels with the sensors.  I rode them around till the tread was gone. 

This weekend I got new rubber on the wheels, and got the old rubber on my extra (original wheels) dismounted. Told the tire guy that if the original wheels didn't have TPMS sensors to not put them on the ND2 wheels.  No sensors found, so regular stems put in the ND2 wheels with new rubber.

This morning was the first drive with the new rubber and no TPMS sensor in the ND2 wheels.  About 9-10 miles into the drive the TPMS light blinks for a bit then holds steady for the rest of the drive.

Some casual looking says that this might be an issue with the sensors, but the wheels it had didn't have sensors?  So I'm confused.

Honda uses a system where there are no sensors, and the car somehow "listens" to the tires.  It needs to be reset with new tires, and there is usually a switch someplace, or it's a menu item.

 Others use wheel speed sensors, because a low pressure tire will rotate faster than the others. 

No clue on Mazda specifics.  Check your pressures and move on.

My guess would be that the system is sensing that there are no sensors or zero pressure.

In reply to L5wolvesf :

I may not have explained it well.

Original tires had no TPMS sensors.  Never had an issue with the TPMS light.  New wheels had sensors.  New rubber and no sensors, light is blinking.

Light on is usually a pressure issue, light blinking???

Yeah it sounds like some kind of tire-sensor-free TPMS system, some manufacturers (I think '00s BMWs for example?) use TC/ABS inputs to detect whether the tires are inflated correctly and they need to be reset when tires are changed.

Having tried typical modern sensor-based TPMS for the first time last year, in terms of detecting punctures it seems kind of useless because it takes 15-30mins of uninterrupted driving for the dash warning light to react. I was a bit more interested in tire temperature data but I haven't tried monitoring that manually yet or manually watching tire pressures to see if they could give useful info before the warning light comes on. But it seems like the warning light would only be useful for notifying the driver of a slow leak.

Edit: Also my modern sensor-based TPMS light stays on solid when the sensors are missing. I haven't seen it blink yet...

Do you see anything on the dash that looks like a TPMS reset button?

https://forum.miata.net/vb/showthread.php?t=702305

I have some memory of a reset process on my mom's '07 BMW 1-series that involved setting the tire pressures, doing a reset in the dash menu and then driving around a bit.

Edit: This thread says "lower part of the dash to the right of the steering wheel":

https://forum.mx5oc.co.uk/t/2018-nd-no-obvious-tpms-switch-or-setting/96377/2

The ND1 used "indirect" TPMS, where it determined pressure loss via the ABS wheel speed sensors. There was some crazy magic sauce in there as well that allowed it to detect if all four tires were low, something a 2002 BMW E39 (to pick a random example) could not do. Here's what it says in the technical manuals:

 Torsion resonant frequency detection With torsion resonant frequency detection, detection of differences in tire air pressure is possible even if the tire pressure of all 4 tires decreases at the same level. This detection method uses the ABS wheel speed sensor signal the same as the dynamic loaded radius detection method. With resonant frequency detection, the signal from the ABS wheel speed sensor is analyzed in single pulse units and various wave frequencies are detected. Among these wave frequencies, the wave frequency synchronized to the air pressure is the torsion resonant frequency. Therefore, by monitoring the torsion resonant frequency, decreases in air pressure can be detected indirectly.

Anyone got a big enough brain to come up with that plan? Not I. There's also a bunch of "misuse" prevention, which includes things like "resetting the system without changing tire pressure". It's pretty darn smart. Anyhow, it works and I wish it hadn't been removed.

You can spot an indirect TPMS car because it has a TPMS "set" button on the dash to the left of the steering wheel. The cutover wasn't that clean, I think the Fiat 124 had direct on some trim models and indirect on others, and the ND MAY have also done the same - I forget.

The reason the light is blinking on Mr_Asa's new tires is because they're not the old ones :) The diameter is probably different since they're new. So the thing to do is to initialize the system. 

• set your tire pressures (duh)
• turn on ignition (starting the car is OK)
• press and hold the TPMS set button until the light flashes a time or two (Mazda seriously says 1 or 2 times, you'd think they'd know) and you get a beep
• drive the car for at least 20 minutes

Keith Tanner said:

There was some crazy magic sauce in there as well

Meanwhile, the NC will set the light if any Ford or Mazda vehicle within 3 miles has a tire that is low.

In reply to Keith Tanner :

Well.  E36 M3.
Now I truly don't know what is going on

Pic from a couple weeks after I got it so it has the original wheels, no tire light, sitting at an intersection:

No TPMS sensors found in those wheels at all.
Looking now, I see no TPMS reset button on the side of the dash/instrument cluster.  So is this year car supposed to have TPMS sensors?

I can't explain how you didn't have a light before, but without a TPMS "set" button you have direct (aka sensor-based) TPMS. And your current light behavior does line up with missing sensors:

The tire pressure monitoring system warning light flashes for 1 min. if a malfunction is detected in the tire pressure monitoring system, and then it illuminates.

The factory manuals for 2017 and 2018 show both direct and indirect TPMS. 2019 shows only direct. The parts fiches don't help, they show a change to the TPMS sensor at car 171016 but it's just a minor one that doesn't matter.

Also, the BBS wheel used on those cars has an MSRP of over $1100.

I'd wonder if there's some wizardry that the dealership might be able to do to turn the light off, but I'd expect you'd know if there was.  I guess I'll get the TPMS sensors put back in when I have time.

I'm so baffled by this.

Build date of 3/18 on the sticker, car 205553, if any of that helps figure this out later.

I can't find any reference to said wizardry in the factory documentation, although I don't have an M-MDS tool to play with.

Have you tried using a code scanner to reset?

In reply to DeadSkunk (Warren) :

Haven't had a chance to find someone with one.

I'm 80% sure that the TPMS light came on when I hit that road debris that necessitated the extra set of wheels.  No pictures to back it up though.

That's pretty confusing. Not sure what's going on. For my '21 if I swap wheels that are sensor-less, my light flash then l stay solid. When I put the sensor wheels on, it goes away within a few minutes. Later I put a set of NC TMPS sensors in my sensor-less wheels, and now the car switches between the two wheelsets without tripping the light. 

Are you absolutely sure the tire guy didn't find any sensors? Perhaps he didn't personally do the work, and passed it to a different tech who didn't both to inform him. Or he broke one while pulling it out and claiming there were none was easier...

In reply to maschinenbau :

It's not hard to break a TPMS sensor when removing a tire. I think that last is a more plausible scenario than the car ignoring a lack of sensors for a few years.