Hi I am looking to change the wheels on my Focus and think I've found a set at last. The only thing is mine have the pressure sensors fitted and the other ones I have found do not. Are they interchangeable between wheels? Just not sure if it's worth changing them over or getting replacements, or just putting them on as they are or will it bring up a fault/flat tyre display on the dash?

I've swapped wheels on my Fiesta and at present I'm living with the fault on the dash. I will be having the sensors refitted at some point because it will be an MOT fail (fortunately I have 2 years 11 months until then). The valve and sensor are two different parts. With the tyre off the wheel you can unscrew the sensor from the valve and just buy new valves for your replacement wheels. You can get them off Ebay for around £15 for a set of four.

Ok that's great, thanks for the info Dan.

Your signature says you have a 2011 Focus. A 2011 Focus MK3 does not have sensors to detect tyre deflation. Until about the 2nd half of 2014 the Focus MK3 did have the (optional) DDS tyre deflation detection system. The DDS uses the ABS sensor data to calculate the speed of each wheel and by comparing these data detects a deflated tyre. The very late Focus MK3 built after about the 2nd half of 2014 have the TPMS tyre deflation system as standard. The TPMS system uses sensors inside each wheel. 

Thanks for clearing that up then, all I was aware of is that it had a tyre pressure system as it has alerted me before. My ignorance for assuming I suppose, but on the plus makes the change of wheels a little cheaper and more straight forward. Thank you also for your speedy reply and info.

If you ever fit new sensors or put them on another car you need to have Ford service or whoever to scan each wheel and that will add the new sensor to the car computer. 

I bought a new sensor. Had it fitted and same message at present until i get them to scan and add to my system. 

Thanks 

You can relearn the tpms sensors yourself with a small unit. I haven't done this myself but it's worth checking the reset sequence works before buying the tool. Will be cheaper than having it done by ford anyway.

https://hiride.com/ford-focus-reset-tpms/

 

https://www.amazon.co.uk/VXDAS-Relearn-Pressure-Programming-Training/dp/B07WDFJKMB/ref=mp_s_a_1_4?adgrpid=114983417179&dchild=1&gclid=EAIaIQobChMIu-zLtv6d8gIVDIFQBh1TCgeGEAAYAiAAEgJQfPD_BwE&hvadid=485158165380&hvdev=m&hvlocint=9046455&hvlocphy=1007542&hvnetw=g&hvqmt=e&hvrand=7186002700783418101&hvtargid=kwd-356663925967&hydadcr=29430_1958608&keywords=tpms+training+tool&qid=1628307588&sr=8-4