Having read through most of the TPMS threads, I thought I'd share this experience of how I ended up fixing mine which ended up being due to a failed antenna.
I did a full rebuild of the cooling system and supercharger on my 5.0 and had the battery disconnected and the front bumper cover removed while I did that work.
When I put it all back together, I got the yellow 'TPMS System Fault' triangle. I took it to the local membership club Tire Center and they diagnosed low batteries in the rear wheel valve stem sensors.
I picked up a couple of VDO SE52081 315Mhz TPMS Sensors (US versions) and the tire center installed these for $10 a piece. The tire center did a forced reset on the TPMS module via the OBDII port and I got the plan view of the car on the message center with each wheel illuminating in yellow as the module automatically re-links to each TPMS sensor.
Unfortunately, the TPMS module returned to the TPMS System Fault triangle after a mile or so and it was back to the drawing board.
I plugged a more sophisticated OBDII reader in and it showed a CA156-93 DTC error which is the left front sensor having a component failure. Since the valve sensor inside the wheel was still showing a readable battery signal, I then switched to diagnosing the antenna.
I removed the forward fender liners and disconnected each TPMS antenna. I used a multimeter to check a couple of things (1) whether either antenna wire was shorting out to the body due to the wires rubbing against the body somewhere inside the front bumper cover (I had noticed a couple of places where the vinyl tape wrap was fraying from contact and re-wrapped a couple of areas when I had the bumper cover off for the cooling system service). (2) whether there was any breaks in continuity in the wires between the antenna connector and the multi plug harness inside the driver side wheel well (one set of antenna wires is green and green/white and the other side is blue and blue/white).
I couldn't find any sign of a short to ground or a break in the harness so I decided to replace the TPMS antenna.
The Siemens 4H23 1A166 AA antennas are used widely on Jaguar, Range Rover and Fords and I found a used one for about $13 on EBay from a 2013 RR Evoque. They aren't specific to left/right or front/rear and you can use the antenna on any corner of the vehicle. The Jaguar OEM part number is C2C24208.
After I put the used sensor in, I did a 'hard reset' by disconnecting both battery cables and then touching the disconnected battery cables together for a few seconds.
When I switched the ignition on, I immediately got some different behavior from the TPMS system on the message center. It showed the outline of the car with each wheel showing yellow interspersed with the yellow TPMS System Fault warning triangle. I took the car for a drive to the store (about 12 miles) and on the way back home (perhaps 15-20 miles into the roundtrip) the TPMS System Fault warning disappeared from the message center.
When I got into the car for the next trip (about a 5-6 mile round trip), the TPMS System Fault warning reappeared along with the vehicle outline and each wheel illuminating in turn before it went out for good.
The next time I used the car, the TPMS System Warning had disappeared permanently from the message center.
After the TPMS System Fault didn't go away when I had changed the antenna, I bought an Autel TS508WF TPMS Diagnostic and reprogramming tool from EBay but the fault went away before the tool was delivered! In all honesty, with most garages charging about $50-60 to diagnose TPMS faults, having this tool is worth the $130 I paid for it.
So there are a couple of takeaways from all of this. The TPMS Antennas are capable of failing, even though they are a very basic assembly. The TPMS system on the X150 will go into a reset mode automatically however it may take a couple of trips for it to properly re-synch with all the TPMS sensors before the TPMS System Fault warning disappears permanently. You know that it is in its reset mode when you see the vehicle outline and the wheels illuminating in each corner on the message screen.
I have also seen the vehicle outline with each wheel illuminating in turn in the message center when the car battery voltage is low FWIW.

 

Good job!

 

what reader did you use?
"I plugged a more sophisticated OBDII reader in and it showed a CA156-93 DTC error which is the left front sensor having a component failure. Since the valve sensor inside the wheel was still showing a readable battery signal, I then switched to diagnosing the antenna."

wj

 

It was a Snap On brand OBD tester that the shop uses where our Range Rover Sport was being worked on. Don't know the model number however the Autel TS508WF handheld TPMS tool will also pull the TPMS DTC codes from the OBDII port. You can either drop some serious cash for the high end 'does everything' tablet style OBDII tool, or just spend $130 on the Autel TS508WF (it retails at $220 but you can find them new on EBay for $120 or so). I use a low cost bluetooth OBDII dongle and the 'Car Scanner' app on my phone to read/reset everything else. https://autel-us.com/products/autel-...ogramming-tool

 

Thanks!
Since I'm really not going to throw more significant money ( I think) into my tpms headache I'll pass on any more specialized testers.
However, I may buy 2 antennas, used, for $20 and swap out one corner at a time, being willing to install-remove-install in order to hopefully solve my nagging problem.

We'll see.
wj

 

Just remember to hard reset the battery by touching both disconnected cables together briefly each time you swap one out and give it time to re-synch automatically. You will know if the antenna is the issue as the vehicle outline will appear on the message system after you change it out with the four corners being lit up in succession while it reads them and resets. Took me 2-3 trips before it was fully resolved. My Autel TPMS sensor reader/programmer arrived today and works well - you just tell it what car and model/year and whether it is a 315 Mhz (US) or 443 Mhz (EU) sensor and it does the rest. You hold it beside each tire valve and it reads the transmitter data including battery level, pressure, temperature and serial number of the TMPS sensor. It had no trouble reading the OEM sensor valves that are still in the front wheels and the new VDO ones that I installed in the rear wheels recently.