I have had this 2007 XKR Convertible for a year. I got a good price with the realization I would probably need to spend a few thousand to get it in tip top shape. Where else can you get a beautiful high performance car with excellent paint and a new top. For the past few months I was thinking I made a bad deal. The ride was inconsistent, steering was quirky, the brakes acted erratically at low speed stops and the transmission seemed to lurch when coming to a slow stop. I saw an impact on handling when the front tires were 2 PSI under inflated, and was trying to see if the other problems might be in the Vehicle Stability Control by operating with the VSC off. It seemed to have a positive influence but was not a complete solution. Then the battery died, thank god.

I have read a few threads where the responses mentioned battery for some strange problems, but as of now it looks like the battery has been the root cause of all these ailments. With a new battery, and the tire pressures set within .5 PSI, it now rides, drives and handles like a $100k GT should.

So the next question is why would they produce a car that is so intolerant of low tire pressure and low voltage and not show these values in a gauge pack? By the time the computer raises the alarm it is probably too late. I can check it through the OBDC but that is like checking the oil on the dip stick. Does anyone know of an A pillar gauge set to monitor these values since there is no other real estate in the cockpit?

 

A failing or weak battery is the cause of many random DTCs chased on these forums. There should be a minimum of 12.6 volts across the terminals with the ignition in the off position for at least ten minutes. If not, the battery should be charged and retested. If the voltage is still low, the battery should be replaced.

Use the search function as this topic of gauges has been discussed many times. You can also use the Torque app with a smart phone to connect with the vehicle via Bluetooth adapter through the OBD port. You can monitor voltage, coolant temperature and STFTs/LTFTs, just to name a few.

 

Something like this???




Search the X150 forums for "replacement of camp2", I think.
Not super cheap, but also not hundreds of $$$. ALMOST $200, but not quite.

 

I suppose they either didn't know they had - state of the art in 2007 (car designed well before then) - or figured people would just go to the dealer (if such problem surfaced in the first few years of ownership).

Your car is well beyond those years...

The good thing is it helps us afford great cars! But you do need to put in DIY effort - including reading the forum - to save grief and $$$. (Exceedingly small price to pay.)

 

Luxurious car owners do not need to be bothered by mundane gauges. At least I'm sure that was the thought process when these were designed. This was also the beginning of the data buss era so there were some learning curves to be overcome. Sadly the cars core development stopped in 2009 with the 5.0 and just got some face lifts and minor tweaks in the newer models. The core electronics date to 2005ish...

 

Jaguar had tried unsuccessfully to make oil pressure and coolant temperature gauges work for more than thirty years. Oil gauges oscillated gently more in relation to centrifugal force than pressure. Temperature gauges were set to remain comfortably in the cool zone so as not to alarm owners. Rather sensibly they gave up with both of these on the XK.

Graham

 

Indeed gauges are designed for confirmation bias- for sheepish consumers
Fuel gauges on most autos are designed to go down more slowly when full and faster when low...so as to create the illusion a tank of gas lasts a long time. They are not linear.

 

Simple.
Do you know what percentage of drivers even know what the correct voltage for operation should be. Take a poll, even here among the elite, the answer will shock you and answer your question. Then ask those who know the voltage if they know how much capacity is required.....
In reality the typical highend car owner does not know where the battery is located.
Yes Jaguar has taken every other reasonable measure known to science. It attempts to calculate capacity left and turns off things automatically in accordance