So, how clever is the Tyre Pressure Monitor TPM

[9fingers]

The other day I swapped tyres front to back to equalise wear and whilst all were correctly inflated to 2.2bar (32psi old money) and the TPM was happy, I noticed a nail in one tyre so I fitted the steel spare which was a 16" with a 205 x 55 tyre whereas the standard ones are 17"  with a 225x 45 tyre. According to Google the difference in circumference (or was it diameter?) is 2.5 mm (ignoring wear).

After about 20 miles of driving the TPM warning popped up I was quite impressed!

 

Now the tyre with the nail has been repaired and refitted and all pressures checked, will the TPM reset itself after some more miles or once triggered, is the only option to tell it to "calm down dear" by resetting it?

 

I'm curious as to how clever it really is?

 

I will leave it for a while to see and report back unless anyone knows for definite that it wont sort itself out.

 

Cheers

Bob

[petecollier]

You need to get all your tyres to the right pressure (sounds like you have already) then reset the system via the ICE screen.

[penguin17]

It's a pretty 'dumb' indirect system that relies on the ABS sensors, measuring the rotational speed of the wheels.  When the sensors detect one wheel is rotating at a different speed then it will call out a TPMS fault.

 

 

[ahenners]

It is pretty good, I had a nail in one of my rear tyres but it was still well inflated and the system warned me whilst it was still easily driveable. 

 

As previous post, reset it in the infotainment under Setup -> Tyres once everything is sorted and it should only notify you again if there's a genuine issue or mismatch in rolling circumference.

[9fingers]

Yes I'm aware of how it works but wondered if it was clever onough to reset it self once it had been triggered. 

Bob

[Ootohere]

No,

'Driver' input is required.

You can set the Front tyres and rears at a different pressure and set the TPMS.

Even set 3 tyres and the spare and the system should be happy, but if there is a warning then the TPMS needs reset.

 

The other day i had a TPMS warning, and 3 tyres had dropped from 38psi to 36psi and one was at 37psi.

Continental ContiSeal tyres fitted and no puncture just a dropping of pressure since last checked and set.

Edited 14 June, 2017 by Awayoffski

[9fingers]

I can confirm what others have said. I left it not reset for about 30 miles and it did not clear the alarm by itself. 

Thanks for all the replies. 

Bob

[Octy0GG]

Have wondered quite how this system works.

 

Guess it must ignore any brief periods of discrepancy otherwise it would trigger every time a wheel locked, spun or you turned a corner, does it just get round this by averaging over a long time period (I noticed that when I had winter tyres fitted without resetting it took about 5 miles to trigger) or is it clever enough to ignore brief discrepancies and possibly even clever enough to only monitor road wheel speeds when the car is travelling in a straight line. 

 

 

 

[9fingers]

Well it took mine about 20 miles after I swapped tyres back to front and had the spare on  before it triggered. Tread depths were 4 and 6.5 mm

Yes, I agree it must take a long term average to give a credible alert.

[nidza]

It must be averaging inputs and then react.

 

This system is actually genius, as it is so simple. No new hardware, it uses what the car already has, only software is improved. Costs zero, but usability quite high.

Edited 22 June, 2017 by nidza
grammar

[9fingers]

Totally agree Nidza. Complete genius to add a useful feature with existing information.

 

Now we need the sat nav on screen speed limit to be compared to your road speed and provide a warning. So simple but not yet joined up Doh!

 

Bob

[BoxerBoy]

On 22 June 2017 at 17:44, 9fingers said:

Totally agree Nidza. Complete genius to add a useful feature with existing information.

 

Now we need the sat nav on screen speed limit to be compared to your road speed and provide a warning. So simple but not yet joined up Doh!

 

Bob

 

Which is why I still often use my stick on GPS device as it has so much more functionality than any built in GPS unit.

[New8avia]

Although it's a passive monitoring system, it's come to my aid several times with screws, nails etc in my tyres. Triggers at about a 10% difference in psi which prompts you to take a look at the offending tyre early on.

 

[Sec8200]

On 3.07.2017 г. at 00:06, New8avia said:

Although it's a passive monitoring system, it's come to my aid several times with screws, nails etc in my tyres. Triggers at about a 10% difference in psi which prompts you to take a look at the offending tyre early on.

 

 

... and to all... what is the threshold for an alarm?

Is it a percentage from last set data, or fixed psi/atm delta?

[skyjawa]

Its rubbish!  I'd much prefer it to be like the sensors in the wheel like my BMW.

 

Missus got a total flat yesterday and it did not come on at all, drove 0.8 miles and realised it was flat and stopped.  It was set last time I pumped up the tyres.  Only came on after the AA put a space saver wheel on to get her home after a couple of miles.

[vrs4011]

I've found it to be a pain in the arse on my company superb 190 4x4......often giving spurious alarms and false indications.

I check my tyre pressures and condition at least weekly and I'd happily forgo TPS to be honest.

[S00perb]

My estate TPS has gone off at least 10 times - false alarms apart from once: 25 miles from home it warned me - I ignored it (you do after so many false alarms) - the next day I woke up to a flat

[juan27]

My experience on my O2 (same system I believe) is that it does not give advance warning of a sudden puncture deflation as it needs data over a longer period of time to trigger. Its only really useful to tell you when a tyre needs pumping up a bit.  

[Oxboll]

I'm having problems with my TPMS too, random false alarms and Skoda says everything is fine!

 

I've started to record every alarm i get!

 

Quote

5/2 2017 - Tire Pressure OK
9/2 2017 - Tire Pressure OK
18/2 2017 - Tire Pressure OK
23/2 2017 - Tire Pressure OK
24/2 2017 - Tire Pressure OK
3/3 2017 - Tire Pressure OK
9/3 2017 - Tire Pressure OK
25/3 2017 - Tire Pressure OK
27/3 2017 - Tire Pressure OK
29/3 2017 - Tire Pressure OK
2/4 2017 - Tire Pressure OK
3/4 2017 - Tire Pressure OK
4/4 2017 - Tire Pressure OK
6/4 2017 - Tire Pressure OK
8/4 2017 - Tire Pressure OK
12/4 2017 - Tire Pressure OK
21/4 2017 - Tire Pressure OK
31/5 2017 - Tire Pressure OK
12/5 2017 - Tire Pressure OK
24/6 2017 - Tire Pressure OK
4/7 2017 - Tire Pressure OK
8/7 2017 - Tire Pressure OK
19/7 2017 - Tire Pressure OK
21/7 2017 - Tire Pressure OK
31/7 2017 - Tire Pressure OK
4/8 2017 - Tire Pressure OK
6/8 2017 - Tire Pressure OK
12/8 2017 - Tire Pressure OK
17/8 2017 - Tire Pressure OK
18/8 2017 - Tire Pressure OK

 

Sure, everything is fine!

[S00perb]

On ‎24‎/‎06‎/‎2017 at 00:19, BoxerBoy said:

 

Which is why I still often use my stick on GPS device as it has so much more functionality than any built in GPS unit.

Same here

On holiday we use both - if they disagree, the Mrs gets to adjudicate