Hi guys,

 

Quick update as i'm about to reach 5000 miles, my tire pressure sensor...is acting up sometimes.

 

Quick acceleration from the lights (no wheels spinning), triggered it and had the unit showing that the pressure on all 4 are incorrect. This is the second time it happened after let's say a bit of spirited driving (all within the legal speed limit and safety of course).

 

First time i had a front right pressure drop of 0.2 (2.3 to 2.1), and the system showed up with a pressure check on the respective wheel, but now all 4 of them lit up with nothing saying whats the problem (pressure loss or gained, just lit up all 4).

 

It all reverted to normal after a switch off and on at the next lights...

 

The actual readings after, all 4 lost 0.05 bar or so over couple of months (2.3 to 2.25 BAR), can it really be so sensitive to pressure drops?

 

Does anyone else has any insight about this? Worth going to the dealer or a tire fix company to stop the slow air leaks?

 

Regards

 

Never seen a system on a Mk3 fabia that shows which tyre pressure has dropped, so no idea really.

 

Have you actually set the cars tyre pressures as you chose to, then set the TPMS?

 

What unit shows all 4 tyres as being correct, is that an accurate tyre pressure gauge.

 

If you are getting a warning it is really just the car picking up on the tyres circumference being a bit different from when the TPMS was set.

For the first issue, the TPMS is indeed saying which tyre pressure dropped, that's how i knew which one to check, and it was right.

 

For checking,I used a pressure indicator, the one with the needle.

 

I did set all 4 as being correct when i last inflated them at the service stop.

 

The last point sounds plausible, as it only happened during acceleration or hard cornering, will keep an eye on when/if it does it again.

Thanks

Best get an accurate Tyre Pressure gauge, they are available at under £10.

Then when you use service stations air compressors you know what pressure is actually in the tyres. 

Set the pressures when cold.

The TPMS is only monitoring a change from what was set at the time.

Sometimes all 4 tyres drop a little pressure and it is not picked up on.

The tyre pressure monitor system does NOT measure your tyre pressures.

It uses the ABS/Speed sensors at each wheel and looks for a wheel/tyre that is travelling faster than it was compared to the rest.

If the tyre pressure goes down QUICKLY the tyre gets smaller and will rotate faster than before.

The TPMS looks for this change. It will NOT notice a slow ( normal air loss ) change in air pressure.

If you never check your tyre pressures and the air pressure drops normally you can get to a point where your tyres have no air in them

and the TPMS has not warned you because there was no quick change.

If during the spirited driving some wheels/tyre were spinning then this is the faster rotation it is noticing especially a driven front wheel/tyre.

 

Thanks AG Falco

Don't forget to reset the TPMS after you have checked/corrected the tyre pressures. ( once a week according to the Highway Code !! )

 

Thanks AG Falco

Don't forget to reset the TPMS after you have checked/corrected the tyre pressures. ( once a week according to the Highway Code !! )

 

Thanks AG Falco

Ermm... I usually do check tire pressure when getting the message... *slight blush*

Three of four wheels keeps up the pressure for months but right back is loosing pressure slooowly, so every 6th or 7th week its time to fill 0,3 bar on that tire. I suppose the warning limit is about there.

AgFalco, thanks for your really informative response.

 

I was skeptical about having a real pressure sensor loss in the wheel, as there are no cables or anything that i could see. The wheel speed check is a great explanation and i'm sure that's how it actually knows when to beep.

 

I do need some further explanations tho:

 

1. Front differential is unlocked (duh), wheels turn at different speeds during a corner, will the system know the steering angle before taking in consideration speed wheel being different?

2. And if the said system know the steering lock, will calculate the angle and speed to determine the rear wheel speed difference?

 

That sounds more complicated, but i am about to do a 1.5k mile trip in late August and driving on the Autobahn with "safety" systems that i do not understand is not comforting.

 

 

Cheers

AgFalco, thanks for your really informative response.

 

I was skeptical about having a real pressure sensor loss in the wheel, as there are no cables or anything that i could see. The wheel speed check is a great explanation and i'm sure that's how it actually knows when to beep.

 

I do need some further explanations tho:

 

1. Front differential is unlocked (duh), wheels turn at different speeds during a corner, will the system know the steering angle before taking in consideration speed wheel being different?

2. And if the said system know the steering lock, will calculate the angle and speed to determine the rear wheel speed difference?

 

That sounds more complicated, but i am about to do a 1.5k mile trip in late August and driving on the Autobahn with "safety" systems that i do not understand is not comforting.

 

 

Cheers

The system doesnt work neither fast or with pin point precision. Take it as it is, a helping hand.

It wont give you any warning if you set the pressure at a dangerous low level either as long as its equal in all four tires. Or set at different levels for the matter.

My TPMS has alerted once in 9 months. One tyre was found to be circa 1.5psi down vs others...but all 'hot'. Pressure corrected, TPMS reset, 200 mile journey completed without further ado. All pressures checked, cold, following day and TPMS reset, just in case and nothing further since April.

Problem believed to be ... Driving on A1 in very wet conditions, very little traffic and holding NSL, rock solid, without any problems. Believe one drive wheel hit standing water, whilst power on, and went over-speed. TPMS registered it and flagged problem. Warning has never re-appeared and tyre pressures are all behaving. As has been pointed out, the system monitors wheel rotational speeds, not tyre pressures and TPMS is, therefore, a somewhat misleading name for the system. However, what else would be a better name? Wheel Rotational Speed Monitoring System...WRSMS, or omit the word Speed and call ot WoRMS? Hmmm. Perhaps not.

No No, just (indirect) TPMS - plus side of this system includes, when, or if you use a second(winter) set of wheels, no extra sensors required + when if a tyre has a slow puncture the silly tyre place does not need to say "I'll need to stick a knife in this to get it off quickly, if not we will trash your sensor".

 

As a wise previous poster said, "this is a helping hand" - and probably quite a handy helping hand!

There are some manufactures that do have a physical/electronic TMPS that actually measure the

tyre pressure and will send this information to the car's dashboard/infotainment system.

It is part of the valve and the sensor/electronics part is inside the tyre.

 

More trouble than they are worth in my opinion.

It's just another reason to ignore the cars tyres.

 

Thanks AG Falco.

TPMS is doing my head in at the moment... it constantly tells me my back left tyre has lost pressure, and often it has been correct - but no obvious tyre damage having checked with several garages. I then check and reset all 4 tyres, it's fine for a little while and then it pops up again - again, usually the back left tyre. 

 

Yesterday I had two new front tyres fitted - updated all the pressures, reset them on the TPMS. Today it's thrown up an alert for all 4 tyres. 

 

From reading this thread, I'm guessing that it's likely a combination of the new tyres and the drop in temperature? If so, it's a bit frustrating that this is all it takes to throw the error up. Never can be too careful with tyres... 

Be sure to check if the rear wheel is getting hot with a sticky brake caliper.

Heating up wheel can heat up a tyre and change the circumference enough for the TPMS to pick up on.

 

You set tyres pressures outside.  If setting inside in a warmer building then that can be an issue. 

 

Have you checked what pressure the fitter put in the tyres, or did you reset the pressures and the TPMS.

http://michelin.co.uk/winter/what-pressure-in-winter-tyres

Not only winter tyres.  Any Tyres and any time.

Edited 29 October, 20187 yr by Offski

4 hours ago, Offski said:

Be sure to check if the rear wheel is getting hot with a sticky brake caliper.

Heating up wheel can heat up a tyre and change the circumference enough for the TPMS to pick up on.

 

You set tyres pressures outside.  If setting inside in a warmer building then that can be an issue. 

 

Have you checked what pressure the fitter put in the tyres, or did you reset the pressures and the TPMS.

http://michelin.co.uk/winter/what-pressure-in-winter-tyres

Not only winter tyres.  Any Tyres and any time.

Yes, all reset after the fitter had put the tyres on (they'd put them on at a lower pressure - I use the ECO recommendation). 

 

Hoping it's not a sticky brake caliper - was only in for a service last week. Will reset them again this evening (outside) and see what happens on the drive home.

If Serviced at a Skoda Main Dealers they are not touching the brakes unless you are paying extra to get Brake Fluid Changed and they are not Doing Servicing And Maintenance on brakes unless you pay for that.

Oil & Filters and look see and report, maybe a top up and some hinge lubricating and an Expensive Free Wash And Vacuum.

 

At least the wheels were off because tyres were changed, years of Main Dealer Servicing can happen and the wheels are never off from when they were fitted at the factory.

My old Volvo developed a problem with 2 tyres always losing pressure, very slowly. After a few re-inflations I had a chat with my trusted tyre guys. Simple fix...the rwo alloys in question had slight corrosion on the inner sealing surfaces casing very slight leakage.  Tyres off, corrosion polished out and end of problem. No charge as I always buy my tyres from them and the manager said it should have been spotted at last change. Proper, old fashioned, service.

 

not saying this is your problem, but worth bearing mind.

With my Volvo wheels and others and other peoples when cleaning beads and sealing tyres still does not work and pressures drop then it is a case of letting down the tyres, 

Tyre weld in and then the pressure up a bit, and spin the wheel / tyre on the Wheel Balancer or on the car, then tyre pressures set correctly.

Or better still, use Puncturesafe which lives in the tyres for the life of the tyre, seals any punctures instantly and permanently, and prevents leakage from wheel rim corrosion. It's a big thing in the motorcycle world and many fleet trucks and cars have it in from the start. Increases safety and prevents downtime. In addition, unlike Tyreweld it doesn't prevent you from carrying out a proper plug and patch repair to a tyre if it is a hole that is too big for Puncture safe to fix (although it will seal a 6mm hole easily and permanently).

Good shout.    Good stuff, but costs.

 The thing with Tyre Weld or other brands sold on Ebay etc is 'much cheapness' and maybe you already have unused and one can does 2 tyres.

Repairing repairable tyres is never really any issue, only some Tyre Fitters make a song and dance.

You remove a tyre, let the 'Tyre Weld dry off or you clean it off, have fun taking off the rubbery stuff.    Obviously professionals are too busy to mess about...