What is the value of resister R408 In CP79A CHASSIS

You can't, without a bypass kit and the orginal key or resister value to use in the bypass kit. The theft system on the truck is a VATS system that uses a resister in the key that must match the resister value in the computer to start the car. No resister match, no start. The kit eliminates the resister key by hard wiring the resister permanently in the vehicle. You still will need the key to mechanically unlock the steering column and turn the ignition cylinder.

i think the crankshaft sensor on the xtrail is not resistive but is a hall effect sensor which generates a digital on/off signal using a semiconductor device and can only be tested by suitable diagnostic equipment using the obd connector, if it turns out be a resistive sensor then about 1000 to 1400 ohms would be the norm value for that type of sensor hope this helps

Often, when multiple, like electrical items are not working, it is the fault of a ground connection.

You need a multimeter with Ohms function (universally present in these) and start checking on the shell of the connectors to a clean, chassis point to see if the resistance is as it should be; nearly zero Ohms on the lowest scale, typically 200 Ohms
Lead resistance should be checked by shorting the two leads (+ and -, red and black) together on that lowest range.
This will be on the order of .2 to .6 Ohms.
Checking from any socket shell (the outside of the socket) to a clean bolt-head or similar, bare-metal point, should show little difference above the shorted-lead value or ~ 1-2 Ohms.

Locating a common chassis ground point is not always easy as these may not be readily visible.

If you find no connection between the socket shell and a chassis-related bare metal point, go to one of the Jeep forums and ask where these ground points are located.
I'm sure yours is not the first instance of this problem.

Good luck-

this will be infinity as there is no connection if the plug is assembled correctly

This sounds like an issue I had. check out this site

Is there a pellet in the key. This type can be bypassed the pellet pushes to resistors outward to a given value from #1 to #14 if you can read key resistance then go to a electronics store a by a resistor that value now crawl under dash by gas pedal you will find a orange cord with two white wires in it place resistor across both wires and cut wires off leaving the ones going up steering column open. turn key on if security light is flashing wrong resistance value. try again. a haynes manual should have all resistance values but key code.

you need to tear down the steering wheel and get to the wires that read the value of the key resister ~~ then you need to solder in a resister of the correct value and from then on the key resister will no longer be needed.

chris...

use a new module ,not a second hand one

I would check the local ground wire. If there is not one there, install one from the chassis to the negative wire going to the fuel pump. If this does not help look for wiring that has corroded and created a resistance, or is chaffed and causing a mild short circuit. Clean the fuse terminals as well. If it uses a relay, check the resistance of the ON current flow. Sometimes contacts can get oxidized and cause a voltage drop across the resistance. I hope this solves your problem.

Relays only have coils inside most of the time. and resistance in these coils is not relevant to diagnosing them. The contacts do develop resistance when they go bad, but there is no standard for a any given resistance. The bestway to check a relay is to energize the coil with 12V. Then checking the resistance to the contact. There should not be any resistance at all. If there is any then the contact is bad.