Land Rover Repair: 2007 Land Rover LR3 cranks but wont start

Question
I have a small import repair shop outside of Wheeling WV.And have 40+ years exp.with imports.This LR3 drove into the shop with head gasket problems.It has the Jaguar 4.4.We replaced the head gaskets and chains and tensioners using factory locking tools.After reassembly the vehicle cranks but wont start.Went over all wiring and grounds.I think it is a immobilizer problem.The remote will not lock or unlock the doors.I wathed a you tube video of  this problem and in the video when the key is inserted in the ignition lock cylinder a message comes up key in ignition.I talked to two Land Rover dealers and asked if I do not get this message is that a sign of no communication with key?.No one seems to know.The nearest dealer is 100 miles from my shop and the owners other key is 800 miles away.I have a Launch scanner but it does not offer me immobilizer function.I have tried discharging memory with battery cables but to no avail.What is a simple way to determine if this is a key problem ?  Thanks Greg

Answer
I don't there is a simple answer to the problem, other than to tell you to buy an Autologic or factory tester for $10,000.

The problem is that you don't have a tester that's able to diagnose the problem, so anything you do is a guess.  There is no reason for a security lockout just because you took the motor apart.  So my first thought is that there is some workmanship issue on the engine - some connector plugged in wrong, etc.  Can the Launch tool show live data like crank sensor signal?  If so, maybe you can check that.

If the Launch cannot show full live data and all input and output for the engine ECU (including drive authorization status) you are out of luck.   If it does show those things you may be able to figure this out.

My bet would be on a mis-wiring of one of the engine connectors.  I would pay particular attention to the cam and crank sensors and whether the cam references were assembled properly.