TPMS

[NickB4]

Hi folks. Since having 4 new tyres on my Audi A4 Allroad 18 months ago, the TPMS does not seem to function, when I switch on the ignition the low tyre pressure light works but it does not show when there is an actual pressure loss in any of the tyres. I have reset the dash computer to the correct tyre pressures but doesn't make any difference. Also, does anyone know where the diagnostics socket is on this model? 

Thanks,  Nick.

Edited May 9, 2023 by NickB4
Addition

[Steve Q]

Obd port should be driverside side footwell. You'll have to look up under the dash. 

[NickB4]

Many thanks Steve, I've located it. N

[Magnet]

Hello Nick,

Probably too simplistic a response, but since your issue started (18 months ago) when you had new tyres fitted, it would suggest it has something to do with the fitment/non fitment of the sensors on the valves. Were these changed at the same time, or did they simply reuse the old valves? 
Kind regards,

Gareth. 

[NickB4]

Hi Gareth. I have been in touch with the tyre fitters/suppliers & they have told me that this vehicle has indirect tpms which means that each wheel is monitored by the abs system NOT like the direct system which has sensors in the valves! So each wheel diameter is monitored & if there is a drop in pressure it is noted & sends a signal to the vehicles computer which  then sends a warning to the dash telling you which tyre/wheel is affected! All very technical. Thanks for your reply. Nick.

[Magnet]

Thanks Nick. That sounds interesting. Does Audi confirm that? 
Perhaps you could let us know. Still something of a coincidence then. 
Kind regards,

Gareth. 
 

[NickB4]

No I  haven't asked Audi yet but from what I have read the indirect systems have conventional rubber valve stems & direct systems have metal ones, strong enough to hold the internal wheel sensors! Mine are rubberised! Audi want the standard charge of £70 just to investigate plus whatever it costs for any parts & labour on top. Hence I am researching the problem & will most probably sort it myself, if I can't I'll manage without them or take it to an independent! Audi really do take the Micky! 

Regards, Nick.

[Magnet]

Hello Nick,

I follow the theory, but there are certainly non-Audi with rubber valves which have a sensor screwed on the inside. Perhaps metal cored, but not inflexible. 
Kind regards,

Gareth. 

[NickB4]

Probably so. VW Audi have been using indirect tpms for some years now apparently... which is good in that tyres don't have to be removed to replace  batteries, my old Passat had the same system & it worked fine (as did the Audi before the new tyres were fitted). I'll keep you informed.  

Regards, Nick.