As a lurker, and I'm not conversant with the Jag system, but let me say that probably won't work. To keep the battery in them from running down, they typically don't transmit unless the tires are turning. That is what "wakes up" the sensors. Won't happen in the spare or pipe.

 

Not a problem, I'm not versed well in the Jag world myself. But I can say that "Physical" tire rotation is not what triggers the sensors to broadcast data.

The spare tire and pipe bomb trick are well documented on many brands of cars (I personally used this on my Lexus IS350...). However, my Lexus was a single channel system, so cabin alerts did not tell you which tire was low, just a tire was low. A single receiving antenna could report all 4 TPMS serial numbers as "OK" to the cars computer. The range of the TPMS transmitters in the tires could obviously reach from the spare tire well to the nearest receiving antenna in the rear wheel well.

I have never triggered my TPMS on my XK so I don't know if it is a single channel or 4 channel system...

Vince

 

The Nissan TPMS works like jjsC6 says -- it's the centripital force of the tire rotation that turns on the valve sensors. In all honesty, it's probably worth the diagnostic fee to take it into the dealer and have them give the system the once over. It could be that something is wrong with the ECU / receiving system and all your other efforts are for naught.

 

I am so sorry it only worked temporarily. I guess I got lucky, maybe worth one last shot, try it again... Good luck! .. I got an engine light warning this morning... checked the code... thermostat not closing off properly and causing low warm up temp... man I just don't want to know!! I reset it.. but will get some of that tape from you! Neil

 

That's totally new to me... The way the system normally functions can certainly give anyone that assumption as rotation allows the TPMS sensor to pass near a transmitting/receiving antenna, but I think you'll find it is simple RF that does the whole trick.

Most that I am aware of are triggered by an electronic request... Very similar to the standard RFID system used in key fobs, only the sensor has a battery for powering the logic circuits and transmitter feeding data back to the car. This is why most tire shops have hand held readers. They hold it near the stem, and send a "wake up" request to the TPMS... The TPMS then responds with a data dump before going back into power saving mode...

Scan tools
TPMS Tool - FAQ - TPMS Frequently Asked Questions
Automotive Service Solutions - Bartec

Some interesting technical reading.
How sensors work - Tyre Pressure Monitoring
http://web.sensor-ic.com:8000/JPCGQZ...m_Overview.pdf
http://ftp.cse.sc.edu/reports/drafts...2-tpms-old.pdf

I don't doubt there is some odd systems I have not heard of out there, but TPMS had been around for some time now in a standard form.

Vince

 

An update: Working on the premise that this is a Low Tire Pressure system/indication, I decided to overinflate the tires to see how that works. Can't have a Low Tire indication if their overinflated to the same pressure imho.

So engine idling (no good reason for that, but...) and inflated each tire to 40psi. Got in the car and the display showed a failure with the red indicator going from one tire to the next randomly. Well drove it anyway and the indication went out ????about a mile later in the drive. Then drove approx 20 miles on the hwy and back home with no fail indicator.

So late I'll deflate them all down to say 35 psi and see how that works out.

The Jaguar system works like the jpgs I attached several posts ago. The monitor broadcasts from the INITIATORS in the wheel well to the pressure sensors in the wheel assys. The pressure sensors feedback pressure, temperature and acceleration to the RECIEVER which in turn passes the information from the pressure sensors back to the Monitor. Then the Monitor sends data via the mux bus to the display IF there is a fault.

After the INITIATORS have served their purpose of identifying the wheel locations, they are not used again during the drive cycle (see jpg attached in my other post).

I don't like driving with 40psi in my tires so I'm going to work my way down the psi chain to find a satisfactory pressure of????????

And I appreciate the LINKS in the other posts above. It helps to be informed.

 

<thinks> What you say makes sense Clever -- I confess that what I know of them is what they told me when I bought the car and I never bothered to double check it.

 

I've ran into a few xf's with this problems. I believe xf, xj, xk are the same tpms system. You may have a bad tpms module.

 

This might be an ambient air temp problem. I drove from Ft Worth Tx to Arapahoe Ne last Wed and had the low tire pressure fault displayed about 95* of the time. The next day the same conditon existed.

This Friday morning I left Arapahoe at 2am and the air temp was 46*and stayed that temperature for most of the trip back to Ft Worth. The low tire pressure fault was not displayed at any time during this trip.

So? It might be temperature related in some way.

Oh, I was surprised. I got 28 mpg going up and 27.4 coming back. Not bad imho. I thought I'd be getting on the order of 22-24 mpg. And this was doing 75-80 mph on the interstate mostly.

 

Any news on your TPMS issue? My 2008 just started doing this as well. I will try Neil's procedure tonight and see if it works for me or not.

 

Cooler weather seems to have effected my problem to the good. Like mentioned in another post, last Aug/Sept I went to Nebraska for a couple of days. I got up to go back to Texas around 2am and the temp was in the 40's AND the display did NOT show the fault all the way back to Ft Worth.

It stayed good up until last week when it failed. So I turned the engine on and idled the car and then, one at a time, let the air down to approx 20psi and then reaired to 30-33psi and the display showed to the good again.

I belive this is temp related and not a TPMS monitor fault or Initiator fault nor reciever fault. The units inside the tire transmit pressure and temperature to the reciever and then on to the monitor then display.

I downloaded the factory manual and did a little reading. IF memory serves........if it's a monitor, initiator, reciever, wiring fault, the display will flash on and off for a given period of time prior to showing the TPMS low tire pressure fault. My car never did this flash on and off business.

I picked the lowering the pressure to 20psi out of the blue. No real good reason for that figure. What I THINK I do know, is when you reair the tires you should have the 'KEY" to ON or idling. I selected to idle the car 'cause I noticed that the battery runs low in a hurry if you just messing around with the key to just ON. I figured that out when trying to fix my clanking antenna problem (resolved with a new mast for $14 bucks).

Also the factory manua suggest upping the pressure approx 3psi and having a go at that to fix the problem. I forget what page that's on.

I think I'm good for the winter and spring but in trouble when June rolls around (Texas).

 

Thanks for the detailed reply. I also am in North Texas and mine started acting up about the time the temp started to drop.

I did the reset trick yesterday. I disconnected the battery for the deflation part with the thinking that I didn't want the system to see the PSI drop. I reconnected, started the car and had to drive down my street (slowly) to get it to see the tires were low. I then aired them back to 30/33 and went for a drive. It started complaining again almost immediately during the first drive, however the last time I drove it last night I saw no issues. Today it is still running clean so I have my fingers crossed.

 

Does anyone else find that its annoying that there's no way for the driver to see the currently measured tyre pressures?
It was a couple of months after buying the car before I discovered that the Jag dealer had inflated the tyres to about 55 psi. (No doubt to make the test drive feel better, but also causing a bubble in the sidewall of one of my tyres).

Does anyone know of any 3rd party gadgets out there than can detect the RF signals from the sensors in the tyres directly and give you a readout? If not, I might start looking at how hard it would be to make one.

Alternatively I'm guessing its possible to read the measured tyre pressures (and a bunch of other good stuff too) from the ODB2. In that case does anyone know of a nice little customizeable ODB2 data display that can be left permanently connected and doesn't look too ugly?

 

My initial thought is that the recommended levels are minimums, and that putting a few extra lbs of pressure above those levels would solve your problem. I suspect you've tried that already.

 

There's a ATEQ VT30 sold online for b/t 200-240 bucks that can read each wheel sensor one at a time, which would be helpful in trouble shooting this type problem. But you have to be within inches of the sender to read it, which is ok with me.

ATEQ TPMS VT30 seems I saw a video of it on YouTube. Seems that video showed a Corvettes dash displaying the TPMS fault but on that car it also gave the owner the actual pressures of each tire on the cars dash.

 

Well, I ran clean for about a day and a half. The warnings returned on Friday. I tried the procedure again only this time I lowered each tire to 19 and then let it sit overnight. The next morning I refilled and all the warnings went away, but didn't stay away for very long. This is getting annoying.

Has anyone tired unplugging the initiators or does that throw a general TMPS failure?

 

Hailers/fstick09-Just reporting back since it appears we are the three in Fort Worth with this common issue. As I reported in my first post, I saw the problem rear its head in summer of '11 then go away the winter of '11-'12, then back this summer. I still feel it is temperature-related but if that's the case, how do we have a real fix that doesn't include electrical tape? Very frustrating since I asked the dealer several months back and they informed me they have "new" computer programs designed to "talk" to the cars better....but then cautioned me that I should wait a while before they try to fix my car which (as I said in previous post) would involve replacing my TMPS module. Sorry, but I am not going to replace a module if they are just guessing IMHO.
As a final note....the temps ave dropped the last several days (temp range of 40-70) and as last winter's experience would have foretold, I do not have the system displaying low tires at all. it seems the car likes the colder weather.....so much for buying a convertible.
FYI, after a drive in the cooler weather (ambient 66 yesterday) and still no issues, I checked my tire pressures. All were 30 except the right front which (oddly) was 26. Obviously not low enough to trigger the system but makes one wonder if the car likes to see a subtle variation. I will air that one back up to 30 to match the rest and see what happens. If stil good, then with temperatures expected to rise this weekend back to the 80's, we'll see what happens. I'll keep y'all posted but would like to hear what is going on with Hailers and fstick09 as well with the cooler temps.

 

I wish mine seemed to go away with the colder days. I am getting the same weather and mine is still going berserk daily. I can do the reset procedure and it will go away for about a day, but then it is right back.

I need to take the car in for it's 60k maint next week, I will have them check it and quote me.

 

Hailers has more or less given up. I drove from Ft Worth to Cotati Ca and back and there is no rhym or reason for it working. It worked right I'd guess about 80% of the time. Going thru Flagstaff at night the temp was 27* and it worked/did not work at times.

I'm inclined to buy another toy, which would be one of those monitors that can read the individual tire sensors.

From the factory manual I gather that if it were a open wire or that sort of thing, then you'd get a flashing warning on the display for a given amount of time then the Low Tire Pressure message. So I've ruled out wiring for now. I drove about 3700 miles and I'm getting used to it not working.

We're all keen to know what the dealership finds out about your car when you take it in.

A side note on Adaptive Cruise Control...................I lost my cruise around Barstow. Not good for someone who not too long ago snapped his right ankle and twisted the ligamets. The thought of driving back using the foot irritated me. I got one of those " Radar sensor blocked" or the like. No, nothing was blocking the area of the radar sensor. Sooooooo, it recovered after fifteen minutes or so. This happened a coupel more times b/t Barstow and San Francisco but never has happened since. I think there should have been a backup mode for cruise in case the "radar" got blocked or that radar sensor goes out. Adaptive cruise control has it's place in life, but not on my car.

 

I have got the blocked cruise a couple of times, but it never lasted for long. I am due for new tires as well as the 60k maint, I'll check with the tire store and see if they can read what the tires are outputting. I can't see it being the wheel sensors since they all report at the same time. I figure it's got to be the TMPS module where they all connect.