Jagular, not sure why you suppose that I even have metal valve caps, let alone am questioning your info. I am grateful for your highlighting this issue! I find it odd that an owner should be expected to anticipate any potential issue with the car and research it - surely Jaguar should be highlighting this simple but probably common issue? How many owners with metal caps have been advised by their dealer to remove them? Not many, I would guess...

 

I was overreacting as usual. Probably the wine.

I agree that Jaguar ought to fix this problem rather than try to blame owners putting readily available standard valve stem caps on their XF and then maybe destroying a tire or worse.

The sad irony is the TPMS has been mandated as a safety device to prevent tire failures. So far the system used by Jaguar has caused tire failures. This is totally unacceptable to me.

 

I was offered a burnt out XFR last year, the 4.2 - story goes a front tire rapidly deflated, fell to bits on the rim and cut a PLASTIC fuel line.....fatality so I declined. I don't know if it had these bloody TPMS things fitted, but to be honest they seem to be more a hazard than a help.

 

This isn't a Jaguar specific issue. Even the average tire store salesman will tell you not to use metal caps on any tire with the TPMS sensor. The metal caps seize on the aluminum stem and the stem will break off if you try to force the cap loose. The stem on my Audi S4 snapped off last year when I tried to remove the metal cap (someone else put on). I suppose anti-seize could be used on the threads if you really wanted to use a metal cap.

 

My point is that could not have happened due to a metal valve cap while vehicle was in motion. Plus I always check my tire pressure and the caps come off very easy. Probably cause they have a rubber insert?

 

It could because the owner checked the tire pressure just before the incident. The corrosion weakens the valve stem.

However, we have not established that a metal cap was to blame. The pics appear to show the rim end of the remains of the valve stem. I know the post describes this as the metal JAG valve cap but unless that is a hex shape it looks to me like the other end which is secured to the rim by a hex nut. The valve stem is also split lengthwise. I think these defective TPMS valve stems are just that: defective. I think Jaguar is disingenuously blaming a non-existent fault to cover up the real fault which is a bad batch of valve stems they have no way of tracking.

Jaguar better get off their collective tushes and recall all the XFs and fit new, known good TPMS valve stems on ALL the cars before the US litigation fraternity eats them alive.

 

Big Cat- Ure one gd LUCKY cat !!The original rear tire OEM size was 285-30 ZR20 not 255's;would that make a difference ? Anyway you 've got 8 lives left .
Take care
Chris Nagle 09 XF SC

 

There is also the fact that at about 75mph a plastic cap (say 1g mass) works on the valve stem with a force of about 1kg. A steel cap (of say 3g mass) will increase that to 3kg. Hit a pothole or a ridge ant it will be a multiple of this! The stem is broken at the exact point where the steel in the cap meets the aluminium in the stem, which is where electrolytic corrosion would act at it's most intense. For some cast alus corrosion can make them even more porous than they were to start with and weaken it without much visible damage. The stem is broken in such a way to make me think it is overly brittle as well. There is no distortion to be seen at all, it has simply cracked. So in summary I would replace all valves right now! I wonder if newer stems are of a more ductile alloy? Get a new one and give it a wack to see of it distorts or simply splinters like the old one.

 

Well , Igot 2 new tires in the rear put on today and 2 new TPMS sensor with them just to be safe with plastic caps. The new Sensors are VDO brand. They are the same freq but I need to know how I can get them programmed or does the dealer have to do it? I am sure there must be a learn mode somewhere I can do or a scan tool one of my friends have that can do it?

 

I hope you got the sensor codes off the new ones before the rubber went on. I have not found any way to deal with new sensors short of having the codes entered by the dealer. The manual says they should be picked up just by driving.....but not my experience.

 

In case you skipped reading part of my post: Replace remaining two valves now! (And i assume you only use plastic caps now?)

 

Yup, Used plastic caps. It seems after driving for a bit my TPMS learned itself to the new sensors? This would be good a sa trip to the dealer will not be needed if so.

 

My understanding is that the TPMS needs to receive the transmissions from each sensor for a few miles to identify which sensor is at which wheel. Probably the wheel rotation pattern had to be recorded for several miles of corners in order for the ECU to figure out which wheel is left rear etc. I don't think you need to record or program any codes. If you swap a pair of wheels around th TPMS system has to be able to figure out what's going on without breaking a tire bead and recording some number.

 

Makes sense but it has not been my experience and not what the dealer techs have told me. Said they often need to enter the Id's directly into the ecu. I have been driving with my snows for 3 months and it's still throwing errors. OEM sensors.

 

After the third TPMS valve failure on my XF, Jaguar finally replaced all four with a new design, under warranty. There is supposed to be a TSB out on this issue.

The new valve stems appear to be black anodized (corrosion protection ). There is a substantial looking collar under the securing nut which provides rigidity where the valve stem meets the rim. Finally, the plastic caps look deeper which reduces the amount if threaded valve stem exposed to corrosion risk.

I recommend all XF owners ask their dealer to update their TPMS to the new style ASAP. Your life may depend on this being done.

 

Is it only on the 2009's that the problem exists or would it include later years? (specifically, 2011 in my case)

I just received some metal valve caps (with the Leaper on them) from my daughter 2 weeks ago. I'm wondering now if I really shouldn't use them or if this is really just a lame excuse being used to cover for weak TPMS's?

 

Only thinking out loud here -

If it does, how far does the internal section of the valve stem project out beyond the rim edge. If it sticks out further than the edge then it must have into contact with the pavement, which in turn would cause deformation, not failure. On the TPMS systems I've seen (granted not a lot) some sensors surprised me at how long they were.

And perhaps I've missed this, but has the remaining tyre tread been checked for a sharp foreign object actually in the tread that could have punctured the tyre, subsequently resulting in the deflation and the cutting action of the rim on the tyre?

 

There is no signs of anything cutting or puncture ofthe tire.Just that nice slice on both sides where it seperated the tread from.

 

Excerpt from a UK XF site on related topic:

If you get an intermittent TPMS fault, especially if it happens after a service or the bumper being replaced, take a look on the floor of the engine bay (the air deflector / oil splash on drive preventer) with a strong torch. If you can see a 5" by 4" oval bit of plastic down there with a wire coming out of it then the TPMS initiator has been removed from the tray and not put back. If it's there, just remove the bolts from the front of your wheelarch liner, feel around for it and slot it back in (at the back of the wind deflector). It should fit right at the back, as close to the wheel as possible behind the liner. Remember to check both initiators at the front. If they forgot one, then they probably forgot both. I fixed one and was disappointed that it didn't fix the problem. It was only when I checked the other that it was sorted.

Now the engineering bit:
For those who are interested, after 5 to 20 minutes of driving the TPMS module transmits to the sensors in the wheel in turn using the initiators as antennae (these tranmit on a low frequency, not the 433/315MHz that the sensors transmit on). There is one in each wheel arch. The sensors inside the wheel then send their codes back to the receiver (which is in the centre console under the double cup holder). This is how the module knows which sensor code is in which wheel. This should also be how it can detect if you put in new sensors (i.e. winter wheels). I don't know whether these initiators are capable of taking a sensor out of 'storage mode' when new, but they should be capable of programming new sensors to the car. It would take 5 to 20 minutes of driving to do it. I suspect the dealer method can do it without the drive.

If an intermittent fault occurs or clears within the first 20 minutes of driving (and you drive longer than that often enough to make it significant), then it's probably something to do with the initiation sequence.

Oh, another nugget I gleaned was that the module gets information on temperature, acceleration (wheel speed) and the actual pressure from the sensor. Not just the 26psi threshold failure, but the actual pressure. I believe (from the Autoenginuity screenshots) that it's also transmitted over CAN. The information is only lost at the instrument cluster. Nothing is stopping Jaguar from upgrading the dash to show us wheel temperatures and pressures like the Porsche system that has been mentioned. Except their refusal to upgrade features! A third party display wouldn't be out of the question, though.

 

UPDATE: It appears Jaguar is going to make good on this deal. They say they will send a check to reimburse me for my tire and 2 TPMS sensors I paid for out of pocket.we shall see if this check shows up in the 6-8 weeks they say it takes.

Now I have to find how I can get my dealer to replace the 2 remaining TPMS sensors and make sure they give me the most updated versions. Any advise on how to word it to my service advisor? I am afraid these last 2 TPMS sensor could give out and I do not want to take any chances with either of them since they are on the front wheels . If it happens on a highway again at a high speed I am surely going to be hurt badly. Please Discuss