Hi Guys,

I own both a Roomster and Octavia Mk 1. I posted the following on the Roomster section, but no reponse. I suspect their are more 'technical guru's' look at this section and the TPMS is likely to be similar on the Mk2 Octavia and Roomster?

2008 Roomster Scout, 1.9tdi. 35k

Last winter, I bought new wheels and tyres for winter use, these were a couple of % smaller than the factory fitted 16" wheels/tyres.

On fitting, the TPMS light came on and I tried to reset it according to the handbook, it would not re-set and the dashboard light has been a continuous feature. This did not bother me since i assumed that maybe the winter tyres were outside the parameters of the system and they were only to be fitted for a few months, I could live with it.

A month ago, I reverted back to the factory fitted 16", adjusted the pressures to 32 psi and still the system won't reset, the light on the dash stays on.

According to the handbook, any fault in the system is indicated by a 'flashing light', my light does not flash, just stays on (which is the position for a 'deflated tyre'), thus this indicates a reduced diameter tyre rather than a system fault, however, all my tyres are at the correct pressure and I have re-checked them a few times.

On pressing the re-set button, the dashboard light blinks once and then just stays on (no 'bong' or other noise to indicate that re-setting has taken place).

To be honest, I am not too fussed about the system not working since I allways regularly check pressures but I believe that a warning light on the dash might be an MOT failure?

Any ideas? Anything I should/can check?

Cheers, Terry

You will most likely know and done this but worth a reminder

You need to press and hold the TP button until it beeps, I believe it cannot be reset on the move.

its not a mot fail yet and will only be on 12 plate onwards cars when they hit 3 years old.

Thanks, lads.

Yes, I have tried to reset using this technique, even holding the button down for a full minute whilst stationary! The only reaction is a micro-blink on pressing the button and then it remains lit, No audible signal. This tells me that it is not re-setting (and that maybe it thinks there is a wheel underinflated).

I think I will inflate the tyres to 40 psi to see if this gives a reaction before de-flating down to normal values.

The trigger for the malfunction was when I fitted the car with winter tyres which were slightly smaller than standard.

However, the system is not telling me there is a fault since it would then have a flashing light. It seems to be checking the system but deciding it can't re-set because it THINKS there is a wheel underinflated.

Thanks for the tip about the MOT situation, the pressure is off a bit now.

I wonder, is it likely a scan with Vag com would reveal anything?

Cheers, Terry

Hi Terry,

So the IPC warning is due to a system failure of some kind, on your vehicle do you have individual pressures displayed?

Generally the failure warning can be triggered by any of the 4 wheels losing signal or the ECU failing.

A number of things to check;

The tyre centre that changed your wheels have not damage one or more of the wheel sensors during the 1st tyre change?

and being a 2008 car with 35k miles, it this the 1st tyre change? It could be that the battery wihin the wheel sensor has reached the end of its life.

Im not sure what Skoda's policy is on sensor to tyre changes replacement?

If you have another car with TPMS and providing Skoda use the same supplier such as Continental or Schrader then you could sequentially substitute a wheel at a time on either vehicle - remember there is normally a learning sequence!

Steve

Edited 1 June, 201214 yr by o_ptic

Hi Terry,

So the IPC warning is due to a system failure of some kind, on your vehicle do you have individual pressures displayed?

Generally the failure warning can be triggered by any of the 4 wheels losing signal or the ECU failing.

A number of things to check;

The tyre centre that changed your wheels have not damage one or more of the wheel sensors during the 1st tyre change?

and being a 2008 car with 35k miles, it this the 1st tyre change? It could be that the battery wihin the wheel sensor has reached the end of its life.

Im not sure what Skoda's policy is on sensor to tyre changes replacement?

If you have another car with TPMS and providing Skoda use the same supplier such as Continental or Schrader then you could sequentially substitute a wheel at a time on either vehicle - remember there is normally a learning sequence!

Steve

There are no sensors for the TPM, it uses the wheel speed pulses from the ABS sensors.

There are no sensors for the TPM, it uses the wheel speed pulses from the ABS sensors.

then its not a true TPM system!

TPMS = Tyre Pressure Monitoring System

So tha Skoda system doesn't actually monitor tyre pressures?

It must therefore use the ABS/ESP wheel speed sensors to measure the rotational speed of the wheel and if the pressure drops the speed will increase.

This is a crude system as it doesnt tell you unless you are 5 to 10 psi out!

Edited 1 June, 201214 yr by o_ptic

Thanks Steve, but Neily03 is correct. The system apparently compares the rolling frequency of each wheel and if one is rolling a bit faster than the others then this is deduced as being because it has deflated. Apparently, the ABS sensor is the' measuring device'.

So, no sensors are fitted to the wheels just the ABS thingy which is within the hub mech' and is undisturbed when changing wheels.

However, you are right, the fault only exhibited itself when I changed the 4 wheels for a winter set-up back in December. So whether I have had the 15" winter wheels on or indeed the factory fitted 16" wheels currently on, the system doesn't want to let me re-set.

The mystery really is the fact that according to the handbook there is no malfunction as such because this would result in a continuous flashing light.

Cheers, Terry

Edited 1 June, 201214 yr by scotsgent

then its not a true TPM system!

TPMS = Tyre Pressure Monitoring System

So tha Skoda system doesn't actually monitor tyre pressures?

It must therefore use the ABS/ESP wheel speed sensors to measure the rotational speed of the wheel and if the pressure drops the speed will increase.

This is a crude system as it doesnt tell you unless you are 5 to 10 psi out!

Indeed, but in practice it works. It's told me of a puncture on the Leon twice, and even triggered when one wheel got hot due to a seized caliper.

OP, I would get it scanned, just for peace of mind.

Then from memory these systems work on a 'per axle' basis and if you swap tyres you'd need to reset the system as it would have remembered the previous setting.

Then from memory these systems work on a 'per axle' basis and if you swap tyres you'd need to reset the system as it would have remembered the previous setting.

The handbook advises resetting if tyres are moved/changed or after checking pressures IIRC.

I've had a bit of grief getting mine reset after a puncture and a slightly different replacement tyre. You need to be stationary, then turn off ignition and restart the car, push the button until the light goes out and it beeps. Then you need to drive continuously at a reasonable speed, I found if you spend too long in traffic the light comes on again at higher speeds. I had to go through the procedure a few times before it reset properly

then its not a true TPM system!

TPMS = Tyre Pressure Monitoring System

So tha Skoda system doesn't actually monitor tyre pressures?

It must therefore use the ABS/ESP wheel speed sensors to measure the rotational speed of the wheel and if the pressure drops the speed will increase.

This is a crude system as it doesnt tell you unless you are 5 to 10 psi out!

True - and I was going to point out how it doesn't tent to warn you unless a tyre is well out.

That said, it's better than nothing, and one of my local dealers of a different brand are regularly removing the 'proper' TPMS systems for customers (at a cost of about £150) because the sensors are so easily damaged by tyre fitters. I can't remember but I think my dad has had his taken out too because he was fed up of paying £120 a time whenever one got damaged or stopped working........

an interesting article;

Believed to be a second Generation Indirect TPMS system as it utilises the wheel speed sensors of the ABS system to learn the radii and various sensors to learn frequency characteristics of tyres what correctly inflated are able to meet the requirements of FMVSS 138 and will be able to be used on vehicles sold in the US. The requirements of the FMVSS are that the TPMS must be able to detect 25% pressure drops in one, two, three or four tyres within 20 minutes whilst driving between 50 and 100 km/h.

This system is also able to warn which tyre has suffered the pressure loss however will still take up to a few minutes to warn of large pressure loss when driving or when driving off on a flat tyre.

The calibration process is generally very similar for different variations of second generation Indirect TPMS and only requires the driver to drive normally, the times vary depending on driving style and speed variations. The calibration process will continue to be performed each time the car is started until complete.

• 0 -> 5 minutes – system able to detect tyre deflation greater than 25%
  
• 5 -> 20 minutes – system able to detect tyre deflation of up to 25%
  
• 20 -> 120 minutes – system fully calibrated
  

Whilst that all sounds good there are disadvantages to the indirect TPMS

• no way of telling which tyre is under inflated as there is only a single warning light
  
• some combinations may not be detected, ie two tyres on the same side or
  the same axle under some specific circumstances won’t trigger the
  warning
  
• no checking of the spare tyre
  
• the calibration time after pressing the TPMS button can be hours (generally 5-15 minutes)
  
• the detection of pressure loss can take anywhere from a few minutes to hours
  
• they cannot detect a small pressure loss, generally around 20 percent is required to trigger the warning
  
• no monitoring of tyre temperature
  
• systems with frequency measuring require the owner to fit similar tyres as fitted at the factory as tyres with softer or harder compounds will have different frequency characteristics to those programmed in at the factory
  
• relies on users to set the system, if they can’t be bothered to check tyres are they going to bother to set the system?
  

The last point is really the major downfall of Indirect TPMS, it requires the driver to recalibrate the system every time the tyres are inflated. If this does not occur the system becomes ineffective and there is no warning to the driver that the TPMS system requires recalibration.

Many drivers are unaware of what TPMS is and even if they are they are not aware that they have to recalibrate the system and this can lull them into a false sense of security and less frequent checking of pressures (after all the car will let the driver know when a tyre needs inflating. Right?).

If the TPMS warning does go off many users see the TPMS button as a reset for the warning, the car than calibrates for this lower pressure and won’t warn until pressures drop a further 20%. The driver assumes that everything is ok as the warning hasn’t come back and keeps driving oblivious to a problem with the pressures.

Have had exactly the same problem with a Roomster Scout.

History so far:

- Summer 2013, TPMS warning light came on solid as yours would not reset.

- Dealer carried out a 'master' reset which turned off warning light, so appeared resolved

- November 2013, light on again, just happened whilst normal driving.

- December 2013, into dealer again.

- Advised there has been a makers advisory requiring a software upgrade. They want to try this first then if not the answer look to changing the reset switch in the car. That sounds an unlikely fault resolution.

Does anyone have any update or have had the software patch applied? Removing the dash bulb would seem best option and just check the tyres regularly as one should anyway......

Thanks, lads.

Yes, I have tried to reset using this technique, even holding the button down for a full minute whilst stationary! The only reaction is a micro-blink on pressing the button and then it remains lit, No audible signal.

Cheers, Terry

I had the same.

It just flashed and then stayed on (after I changed to smaller winter wheels).

But after holding the button down longer (say 20secs),

the light turned off :-)

Have u got it sorted now?

And wot was the cause?

Scanning the car with VCDS would show if any faults are present.

Sent from my Nexus 4 using Tapatalk

It can be turned off with VCDS bud as it's under warranty, I would persist with the dealer.

By way of an update to my Roomster TPMS problem. Car has been in main dealer for just over a week. Story is that whilst applying a software update a spike was generated and hit the ABS ECU. Lots of scratching of heads at Skoda factory which resulted in a new ECU being fitted at a cost to the dealer of around £1400. Apparently situation totally unknown and have left my dealer trying to recover his expense from Skoda themselves as the dealer was acting under factory instructions. Very unfortunate, thank goodness I used a main dealer but do feel for them under the circumstances. Really hope this is the end of the story.