My car has developed errors when raining with the TPMS. It pops on, cycles different tires showing low pressure and then goes out. Comes back on showing other tires, and thens goes back off.

Cycles like that randomly. Happened once after a car wash as well.

Works fine when dry.

Anybody else expericance this? As far as I know, the sensors are original 2010 units.

The tires do not leak, always read 40psi and do not have to keep adding air.

 

Has this been a recent problem or one that has always plagued you?

What kind of valve caps you have on?..Just for the hell of it..just hose down the tires/wheels and valve stems only and drive away without and with the caps on...

 

At 40psi cooling the tire with water can change the pressure in the tires depending on the ambient temps and the tire internal temps. Maybe enough to temporarily set off the TPMS.

 

What size rims and what kind of tires? 40 Psi sounds kind of high

 

Only for a cold tire. Once the tire warms up it can get quite hot. Tire pressure goes up accordingly. That's why you never adjust tire pressures on a hot tire. This idea is quite a good one actually. Might explain the issue.

The TPMS sensors are temperature and pressure sensors and at supposed to send both sets of data to the TPMS ECU, however, these false signals are happening for no apparent reason and are v annoying.

If this poster is running 40 psi cold then that is far too high.

 

Good points being made about varing Pressures due to temp changes..

Solution would be to have all four tires and include the spare..be pressurized with Nitrogen..this will stabilize the pressures as Nitrogen is an inert gas and WILL NOT EXPAND or CONTRACT with temp increase or decrease changes.

 

I've been reading a lot about nitrogen for inflating tires. Ambient air contains about 70% nitrogen anyway. Nitrogen molecules are larger than "air" molecules, so the idea is the nitrogen will not escape through the rubber tires as fast as ambient air, therefore would be less prone to cause tire pressure drops. 5th Gear had a segment on the differences on a car equipped with tires inflated with air and nitrogen. In their tests, the pressure increased more with the nitrogen inflated tires than tires inflated with "air" inflated tires. Both of my vehicles came with nitrogen inflated tires and both of them have had TPMS issues. I am at a loss as to which is the better way to go. Living in the SE, USA, there are not a lot extreme temp changes normally, so I don't see a real need to go with nitrogen. This may just be a ploy to charge more to fill your tires. Air has worked fine for 100 years, so I see no real value in using 100% nitrogen in tires. Maybe someone can point me in a different direction!

 

Never Mind, I don't want to get into a big hairy discussion...The benefit mostly of using Nitrogen is:, Inert, Noncorrosive and doesn't support oxidation, Will not support a fire, Atoms are larger than O2 and will escape less from tires through natural attrition, Controversy and Pro-Cons will always be part of this topic..People will do what they feel best doing....for the record according to the laws of gases;..Nitrogen will expand 1psi/10 degrees(F) of temp increase.

Good luck

 

Boyle's Law applies to all gases. The only real advantage to nitrogen fill is less water vapour due to the process used to "distill" the nitrogen from ordinary air.

The main disadvantage is you cannot conveniently adjust tire pressures seasonally unless you have convenient access to compressed nitrogen.

http://www.getnitrogen.org/pdf/graham.pdf

Eventually, if you keep refilling your tires with ordinary air the difference in permeation rates will leave you with pure nitrogen in your tires anyway.

8-)

 

It has nothing to do with Tire pressure level or rain. I know what the problem is, but I don't want to tell you so you wouldn't have to take your car to the dealer to get it fixed. Assuming the dealer knows what the fix is.

 

I know it is not pressure issues or cooling effect of water causing the sensors to "alarm".

I would like to know what is going on. I am waiting on new headlights and interior lights control board to be recieved at the dealer and the parts should be in soon.

If you don't want to post up here to be flamed by the guys that always feel the need to blame the owner, then send me a private message.

It is sad that some automatically assume you don't know how to read a pressure gauge or know anything about automobiles. As bad as dealing with the majority "service managers" that think the customer is clueless.

I would appreciate it if you you message me with your info.

 

Was this issue ever resolved? Have the same problem with my 09 xf premium. Well this is just one of the problems that have started over the last month. I have a appointment with the dealer set up but would like to have an idea of the problem before it goes in.

 

No, I have not made it to the dealer since they are 100 miles away.

There are some on this site that won't tell us what this is for fear we may ask to have it repaired.

If you find out what it is, please tell me...

 

There are two main sources of trouble: the transmitters on the valve stems which usually fault one at a time (although this may produce issues with the whole system for all I know as each transmits its location as well as pressure and temperature data) and issues with the "control unit" which may result from the four receivers having difficulty reading the valve stem signals (my pet theory).

This assumes the control unit tests out as fine. I strongly suspect that a lot of control units are changed out when they don't need to be.

There are four receivers behind or ahead of each wheel but again if one gets dislodged or fails you should get a fault from that wheel I should have thought.

In my local area we get strong atmospheric disturbances periodically, especially during winter. All types of radio signals seem to be adversely affected during these events from commercial radio (not digital) to the remotely signalled mini weather station on my coffee table.

As long as the fault you are experiencing is intermittent and perhaps apparently weather related I recommend you consider just ignoring it. If I am correct, and this is just theorizing, then there is no fix.

Alternatively, if your valve stems are more than five years old it is possible the battery in each of all four valve stem transmitters are going dead at the same time. For the cost it might be worthwhile fitting four new OEM valve stems as they have a designed service life intended to match tire life which is maximum 5-7 years regardless of tread life remaining. I'd avoid fitting any sort of cheap valve stem.

 

My car has just started doing this: TPMS will come on for 1 tire and then show another tire and then another, etc. Then the alarm will disappear from the DIC. It will show up again, randomly, and repeat the process.

Going to the dealer 7/2/2013

 

I too have seen this problem but it has eluded the dealership as they have not been able to duplicate the problem. On my car it is "weather" related, but not rain.

I thought it was temperature, but seems to be sunshine. After several weeks of not seeing the issue, on a one and a half hour trip in strong sunshine and about 23 C temperatures, the display came on changed to and fro among all four wheels and then went away for a few minutes. The next two days were the same and we were in the open pretty much all the time. I tried pumping a few (3) more PSI into the tyres but it made no difference. Yesterday we returned home in similar temperatures, but cloud covered and saw no alerts. Today we are at 26C but cloud covered and no alerts.

I can only suspect something is getting hot from the sun, but as not all four wheels are in the sun at the same time, would think it is heat on the controller in some way.

Any ideas would be very welcome. The dealership are keen, but without direct evidence are not able to resolve it. They did explain that another XF they serviced exhibited the problem when with them and they were authorised to replace the controller.

 

Boyle's law applies in the same way to all gases and the expansion factor is a constant:

Boyle's law - Wikipedia, the free encyclopedia

So ordinary air also changes pressure by the exact same amount as N2 or any other gas, about 1psi every 5C.

Ordinary air is nearly 80% N2 so paying for 98% N2 is boneheaded.

N2 molecules are almost exactly the same size as O2 molecules. Ironically, this idea that N2 molecules are so big they won't leak through rubber (which is totally ridiculous) if true would mean you could get pure N2 in your tires by refilling with ordinary air. Ironically, a slow leak would speed up this process, except that the whole idea is just pure BS.


O2 is not flammable, only fuels are flammable in the presence of ignition and O2. Since the air outside the tire is approximately 20% O2 the tire is going to burn regardless of what's inside the tire.

What causes issues with tire pressures is water vapour. N2 in pressurized bottles is dry but then so is compressed air from a properly maintained compressor.

 

I suspect the issue may be interference with the radio signals under some atmospheric conditions. Or low batteries in the senders in the tires. They last about five years from activation.

 

On the second visit to the dealer for my TPMS issue of random tire display, they replaced the TPMS controller. So far, no false displays.

 

This is the fix several people have reported. When all the sensors are faulting it is most likely the control unit.