- My model of MX-5 is: 1.5 Sport Nav
- I’m based near: Port Talbot
- I’m looking for technical help or recommendations on: Pressure Monitor
Hey folks, I have a quick question about the tyre monitor system on the ND… Last week I had the beeper going off and a tyre warning message. Sadly it was a whopping nail in the rear passenger tyre and a new tyre was needed… That was gutting but nevermind…
A week later and the tyre monitor beeped again tonight just after leaving work… I left the office car park and as soon as I joined the M4, 2 minutes in it triggered the alert…
I brought the car home and checked all the pressures on my electric pump and all four tyres were between 31-32psi… So I’m stumped as to why the monitor triggered?
Anyone else had this issue before? for now I’ve reset the monitor and will see how I get on tomorrow. I was told that temperature changes and high winds can trigger it and today I was driving home in high winds… Any suggestions 
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Have you done a reset of the pressure monitor?
What year is you ND?
Different years have different monitoring methods that could explain this behavior
Also, as it is a 1.5 I am assuming it doesn’t have an LSD?
Two factors here.
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Is the new tyre the same make as the others, with the same tread pattern and rolling resistance? ie do all the type codes match.
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Are the other tyres quite well worn, ie a different circumference from the new one.
Mismatched tyres will throw up errors through the ABS method of measuring tyre pressure, which usually takes a few minutes of driving.
The cure is to have the same make AND type AND degree of wear on both tyres on the axle. This might mean one puncture requiring two replacements!!
Been there and done it a couple of times over the years… 
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As Ian says there are different types. Up to about 2018 they worked on comparing wheel rotations. Later they were equipped with pressure sensor valves. The first kind will need a reset. Sounds like you’ve done it.
Pressure should be 29psi.
You should reset whenever you adjust the pressures, whther the light is on or not.
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Hi folks, sorry for the late reply…
Yes its a 2015 so I don’t have the pressure modules on the valves, its the old school wheel speed sensors that do the measuring. So far since my last reset, I’ve had no lights luckily! When changing the tyre I asked them to keep it the same brand/model as I’m picky with my tyres haha
Cheers for all the replies by the way
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I have had that problem. My 2015 went off on a hot day going over woohead glossop. Stoped & looked at the tyres & seemed ok. Carried on down to Nottingham. Let tyres cool overnight & checked with a tyre pressure gauge ( didn’t think to use the gauge on the supplied pump ) anyways tyres pressure, all four were Bob on. Pressed reset button & all tickety boo. Spoke to a mech & he said tpms can be very sensitive & the combination of hot day & twisty roads, hot roads could have increased pressure causing alarm. I suppose they are safety feature but they can be a bloody nuisance.
I have never had a car whose tyre pressuring monitoring was so sensitive . I have lost count of the number of times when a hot or cold day triggered excited beeps and warning lights. All well and good , better safe than sorry, but it is tempting to dismiss it as crying wolf . I am glad I don’t - on one stretch of that well known oxymoron , the smart motorway , the warning triggered and checking as soon as I could , after ten buttock- clenching miles - I found one tyre was at 17psi . It is easy enough to tell when it’s serious - accelerate briskly and lift off sharply. If the car is pulling either way , it is serious !
Mine went off a couple of days ago, for no apparant reason i could see, at least it is easy to reset! (2015 ND)
I carry a small battery inflator which includes a tyre guage in my car. It comes in handy on group drives if anyone needs a quick check.
Also you have to reset the monitor esch time you pump up the tyres. Which I didnt know until soneone told me.
This is tge one I have.
The passive TPMS on my old Mazda 6 once triggered at 70mph on the M62. Cue quick diversion to nearest Shell, buying something pointless to get change for the airline, then finding there was absolutely nothing wrong. Dirt or spray seems to upset the reading.
A few months later and the tyre warning is still triggering every other day, drives me crazy! I think its down to the temperature, in this heat we’ve been having this week the tyre monitor is going off pretty much daily. Yet the tyres are fine… A crazy system I must say… Still love my 5 though haha
The Mazda 3 allows you to see tyre pressures while driving. After several miles at motorway speeds, they increase by 3psi from cold* due merely to friction. Direct sun and an increase in ambient temperature will, of course, push this higher. A 5 or 6 psi increase isn’t unusual if you check the tyres at 15 deg in the shade early on, and drive in full sun later in the day.
It sounds as if the ND warning is just trigger-happy,
*this 3psi increase is a valid way to determine the correct cold pressure for a new tyre size, if there is no manufacturer figure available
