TPMS!

[Mercurios2011]

hello there peeps, so here i am again finding myself somewhat lost

my TPMS sensors seem to be having a mind of their own , getting the following codes , but they are intermittent, started yesterday on my way home , check tires and all are good an to proper tire pressure , drove the car again last night and the light was off

this morning on my way to work it was off , then came back on not even 3 mins before arriving at work , I did check the fuses last night and they where all good ,battery few months old and in good condition ,grounds clean tight

so anyhow these are the codes I get :U0401-68 ,P169F-00 , B2872-60 (tpms at fault)

I do have 4 tpms sensors with less that 200 miles on my other rims, and I have a the programmer which takes 5 mins to calibrate

any suggestions or have someone had a similar problem ?

thanks in advance and have a good week end yall!

 

[Handy Andy]

I use both a summer and winter tire rotation, so one set the OEM "spokes" I got with the vehicle - has TPMS - but the others - the winter are a more simpler 15" Steel rim with No TPMS - but I keep the OEM ones in the Garage next to the vehicle when I park overnight - so they don't seem to want to cause a TPMS fault unless I'm away from quite a while.

So to me to have your condition show up - the TPMS sensors result codes are telling me your TPMS are not Motorcraft - or else they would have not needed any syncing - good to go from the start sort of thing.

So if the older TPMS still works, just park your car in the Garage and place your other tires with their working TPMS units (on the rims and properly inflated) in the same room, they'll callout and the FORD TPMS on the older rims will answer and help clear those codes.

Heres' the rub, if you drive more than 30 minutes to work, those TPMS units are not jiving with the Fiestas expected FoMoCo, then the TPMS fault will show up and you get the light.

So if you have a long commute and you park next to cars that have aftermarket TPMS' units, they will fight each other because your car can't validate the TPMS response is it's own. You can try to "resync" them but I don't think that would work, for if the TPMS you have doesn't produce a response that FoMoCo ones can do - then the unit thinks it's another one from another car nearby and just start ignoring the callout.

The reason for that is how the TPMS in the vehicle is validated, it uses a string ID on the frequency, but if the string is the wrong length or it can't parse the string due to a number or letter in the string is in the wrong place (the PSI reading for example) that string is interpreted as from another vehicle using the same frequency, but not the FoMoCo type that has the proper ID string

This is why those FCC-ID's are kind of important becasue not just the frequency, but the modulation type, the format of the string and where the needed data is located on it (that string) - is important - else it can't sort out the other signals from other vehicles as being it's own becasue other TPMS units will attempt to respond to your vehicle callout and return data at the right frequency, but it's the wrong modualtion or ID string is not formatted correctly for your car to interpret it as FoMoCo.

 

[Mercurios2011]

I use both a summer and winter tire rotation, so one set the OEM "spokes" I got with the vehicle - has TPMS - but the others - the winter are a more simpler 15" Steel rim with No TPMS - but I keep the OEM ones in the Garage next to the vehicle when I park overnight - so they don't seem to want to cause a TPMS fault unless I'm away from quite a while.

So to me to have your condition show up - the TPMS sensors result codes are telling me your TPMS are not Motorcraft - or else they would have not needed any syncing - good to go from the start sort of thing.

So if the older TPMS still works, just park your car in the Garage and place your other tires with their working TPMS units (on the rims and properly inflated) in the same room, they'll callout and the FORD TPMS on the older rims will answer and help clear those codes.

Heres' the rub, if you drive more than 30 minutes to work, those TPMS units are not jiving with the Fiestas expected FoMoCo, then the TPMS fault will show up and you get the light.

So if you have a long commute and you park next to cars that have aftermarket TPMS' units, they will fight each other because your car can't validate the TPMS response is it's own. You can try to "resync" them but I don't think that would work, for if the TPMS you have doesn't produce a response that FoMoCo ones can do - then the unit thinks it's another one from another car nearby and just start ignoring the callout.

The reason for that is how the TPMS in the vehicle is validated, it uses a string ID on the frequency, but if the string is the wrong length or it can't parse the string due to a number or letter in the string is in the wrong place (the PSI reading for example) that string is interpreted as from another vehicle using the same frequency, but not the FoMoCo type that has the proper ID string

This is why those FCC-ID's are kind of important becasue not just the frequency, but the modulation type, the format of the string and where the needed data is located on it (that string) - is important - else it can't sort out the other signals from other vehicles as being it's own becasue other TPMS units will attempt to respond to your vehicle callout and return data at the right frequency, but it's the wrong modualtion or ID string is not formatted correctly for your car to interpret it as FoMoCo.

The tpms sensors are OEM Ford and never been replaced.
The other set i have are installed in some aftermarket wheels that I bought, drove a week and took em off because they end up being heavier than the oems, so re installed the OEM wheels back on and this is the 1st time I had issues with them ,drove car yesterday and again light didn't came on till reach destination. I will probably end up replacing them anyway, just wanted to make sure i didn't miss anything before going to the tire shop . Hopefully i can remove the " new" ones without damaging them and just get them swap

 

[Handy Andy]

They may just have a dead or weak battery - the sad part about all this is it seems to fit the issue of that callout - it will only let so many minutes of silence pass until it gives up and sets the light. IT may also signal some other issues as well, like those other cars you drive next to, might have TPMS squealing like a pig due to low tire pressure and if you have bumpy roads - a loose or weak battery gives an intermittent signal - or a weak one, it will set the light on that too.

 

[Mercurios2011]

They may just have a dead or weak battery - the sad part about all this is it seems to fit the issue of that callout - it will only let so many minutes of silence pass until it gives up and sets the light. IT may also signal some other issues as well, like those other cars you drive next to, might have TPMS squealing like a pig due to low tire pressure and if you have bumpy roads - a loose or weak battery gives an intermittent signal - or a weak one, it will set the light on that too.

Today omw to work at 30 min mark the light came ,then when I left work it came on inmediatly ,tomorrow morning we'll see ,but you are right and didn't even think about that ,either way the tire will have to come off ,to at wich point i rather just have em replace