P0191 on your X-type

A P0191 on your Jaguar X-type means that you the computer sees a problem with the IP sensor reading. (IP stands for Injector Pressure). Since the computer sees a problem with the sensor it ignores it and uses the default value of 55.11 psi and flags the code.

To diagnose this code all you have to do is unplug the sensor, hook your voltmeter leads to the connector (needle like leads so as to not mess up the connector) and read a reference voltage, usually around 5 volts. If you see 5 volts. Those sensors never go bad (I never changed one but hey, you might be the lucky one) so here is a least of things to check:

• Check closely for leaks: as funny as you might look while doing this, place your car on Jack stands and smell around making sure you don't smell any gas.
• Plugged up fuel filter, if you never changed the fuel filter, is time to change it, clear the code and see what happens. Here is the link to the fuel filter: FRAM G7143 In-Line Fuel Filter

If you don't see 5 volts then there is a problem with either your computer or a wire in between (but wires seldom go bad by themselves). 

If there is 5 volts, you changed the fuel filter and the code came back and you don't have any leaks then you might need an IP sensor, comment on this code if you do since I never done one!

Here are some links to a multi-meter and some needle like leads:

• Craftsman 34-82141 Digital Multimeter with 8 Functions and 20 Ranges
• INNOVA 3394 Replacement Digital Multimeter Probe Lead 

The second probe leads are great for back probing without messing up the connector