This may be useful to somebody.

 

This warning message started appearing recently followed by the orange warning triangle and ‘front assist not available’ message. As my SE spec car does not have adaptive cruise control the cruise control still worked, so this thing was an irritating nuisance rather than a serious fault.  The handbook merely says to wash the front of the sensor (the black rectangle thing in the middle of the front grille) and check for dirt etc.  Well, I did that, and not unexpectedly it made no difference.

 

Lifting the bonnet, I could just about get my fingers down to touch the edge of the sensor, and feel for anything stuck there, nothing apart from a tiny, tiny part of a spider’s web, not sufficient I feel to upset a millimetric radar.  Then I noticed the front left Tyre looked slightly flat. Checking pressures showed that it was just under 0.4 bar (6 psi) low, and the others were slightly low by 1-2 psi. After inflating the tyres to the correct value (and resetting the TPS), I am happy to say the sensor is now working again and after driving the car for a couple of days and 60 miles has given no further annoying problems

 

Hopefully it will stay that way!

 

I forgot to say that the TPS did not report a Tyre pressure loss.

1 hour ago, John2022 said:

This may be useful to somebody.

 

This warning message started appearing recently followed by the orange warning triangle and ‘front assist not available’ message. As my SE spec car does not have adaptive cruise control the cruise control still worked, so this thing was an irritating nuisance rather than a serious fault.  The handbook merely says to wash the front of the sensor (the black rectangle thing in the middle of the front grille) and check for dirt etc.  Well, I did that, and not unexpectedly it made no difference.

 

Lifting the bonnet, I could just about get my fingers down to touch the edge of the sensor, and feel for anything stuck there, nothing apart from a tiny, tiny part of a spider’s web, not sufficient I feel to upset a millimetric radar.  Then I noticed the front left Tyre looked slightly flat. Checking pressures showed that it was just under 0.4 bar (6 psi) low, and the others were slightly low by 1-2 psi. After inflating the tyres to the correct value (and resetting the TPS), I am happy to say the sensor is now working again and after driving the car for a couple of days and 60 miles has given no further annoying problems

 

Hopefully it will stay that way!

 

I forgot to say that the TPS did not report a Tyre pressure loss.

If I recall correctly, indirect TPMS will not trigger a warning until at least 0.5 bar drop, That may be why it didn't flag.

I think re-inflation of the tyre seemingly fixing the front assist may be coincidental, if the TPMS warning hadn't triggered. 

Edited 7 November, 20232 yr by Warrior193
correction

44 minutes ago, Warrior193 said:

If I recall correctly, indirect TPMS will not trigger a warning until at least 0.5 bar drop, That may be why it didn't flag.

I think re-inflation of the tyre seemingly fixing the front assist may be coincidental, if the TPMS warning hadn't triggered. 

Well I can't be certain and something else may be going of course. Perhaps I did dislodge something with my finger tips, or moved the sensor back into position (if it had shifted) but I could barely touch the thing. What I did not mention was that just before the yellow triangle came on, a car approached from a side turning on the left. It was quite fast but I could see that it was slowing down so I wasn't worried, within a second the Front Assist flagged up a 'your going to die graphic' and then became unavailable (thankfully). I have associated that incident with the low pressure in the left front tyre. Dunno really just have to wait and see. 

Did your front assist go into full ABS mode? You can't mistake it when it does.

The radar sensor on my Octavia does seem to be slightly biased towards obstructions on the left side.  

46 minutes ago, Warrior193 said:

Did your front assist go into full ABS mode? You can't mistake it when it does.

The radar sensor on my Octavia does seem to be slightly biased towards obstructions on the left side.  

No it didn't. In fact I've never triggered the ABS (yet).

Had my Scala for 3.5 years now,  I get the Front Assist error every time there is any form of light mist in the weather.  That can include very fine rain, fog or indeed mist.  All it means is that the detection system to predict an impact and apply the brakes a spilt second quicker than yourself will not be available.   

It seems to be that the density of the fine water build up or possible humidity causes the sensor to become impaired.  Driving for long enough through said weather condition will eventually get the error to clear.  A good tip is to use a rinse aid or hydrophobic coating in your car wash routine and this will help water run off the sensor in misty conditions.

 

Regarding the TPMS sensors, the ones fitted to the Scala are simply rolling resistance sensors, not actual pressure sensors.  This means they are not incredibly accurate and can vary in performance based on tyre size, driving style, and all sorts.  It also means that if all 4 tyres deflate in a uniform fashion the sensors wont pick up on any anomaly in rolling resistance.  A tip, good local independent garages will offer free tyre checks especially in the winter, if your tyres are low they will inflate them for free.  I get mine done every 3-4months.

 

Hope this helps

The sensors can get blocked by muddy water. wet leaves, dead flies, snow etc

 

Sometimes clears itself after few miles, occasionally will need wipe over then clears itself.  Probably coincidence that didn't reoccur after pumping up tyres.

John, Steve when you both say clean the sensor I assume that you mean the front surface on the grill, rather than the separate box  type thing that I could just feel behind it. I understand you when you say that water mist, crud etc can interfere with the thing and I did 'clean' the front surface and it made no apparent difference. It could be however that the my wipe over with a wet cloth was not good enough, At the moment its raining cats and dogs, but when it stops I'll give it another clean, properly this time. However it worked yesterday so perhaps its good. 

Thanks  

19 hours ago, Steve8O said:

Had my Scala for 3.5 years now,  I get the Front Assist error every time there is any form of light mist in the weather.  That can include very fine rain, fog or indeed mist.  All it means is that the detection system to predict an impact and apply the brakes a spilt second quicker than yourself will not be available.   

It seems to be that the density of the fine water build up or possible humidity causes the sensor to become impaired.  Driving for long enough through said weather condition will eventually get the error to clear.  A good tip is to use a rinse aid or hydrophobic coating in your car wash routine and this will help water run off the sensor in misty conditions.

 

Regarding the TPMS sensors, the ones fitted to the Scala are simply rolling resistance sensors, not actual pressure sensors.  This means they are not incredibly accurate and can vary in performance based on tyre size, driving style, and all sorts.  It also means that if all 4 tyres deflate in a uniform fashion the sensors wont pick up on any anomaly in rolling resistance.  A tip, good local independent garages will offer free tyre checks especially in the winter, if your tyres are low they will inflate them for free.  I get mine done every 3-4months.

 

Hope this helps

Correction, the indirect TPMS works off data from the ABS system - it flags when there is a certain measured difference between rotational speeds of the wheels, not from rolling resistance.

Well I gave the car a wash and quick clean this afternoon and had another poke around the sensor with my finger, this time from the front of the grill. Found a few more wisps of spiders web (we seem to have had an epidemic of the things this autumn) from around the sensor, For luck I washed the front of the sensor properly and gave it a quick wax polish 😀. Time will tell, hopefully I'm off to the channel coast tomorrow which is a good hours drive each way, If it stays working I'll forget all about it, if not then I'll report it as a fault when the car goes in for its first service in a couple of weeks or so.

It worked today in both dry weather and heavy rain so i'll forget about it .... hopefully for a long time!