A3 2015 computer says engine failed to start see dealer

Well the alternator only gets involved after the engine starts.
And yes the security system could lock out the engine from starting.
You would need to find out if the chip in the key has failed. If you don't have a spare key, you may need the dealer or a locksmith to take a look.
The engine computer grounds a starter relay in the fuse box when the key switch is turned to start. So that relay, or the neutral safety switch could also be faulty. You should be able to jumper that relay and make the engine crank.

This warning means that a fault has occurred that would have disabled the car in older models, the computer control has worked around the fault to avoid stranding you with a non operational car. You need to see a dealer or a well equipped shop and have the computer scanned for the fault code or codes that are stored when this happens. The engineers who design cars and trucks call this "Failure Mode Strategy"

If this is a Catera the engine control module may be bad, While working at dealership had serveral do that

Its likely a sensor has failed , not allowing you
onboard computer to control everything.
The failsafe is meant to get you home or to the dealer.

VSC and TRAC lights will come on any time the check engine light does to reduce engine load. As such these lights being on may have nothing to do with the why the check engine light came on.

If the check engine light is on, a trouble code(s) has been stored in the computer that points to the problem area. The dealer should have read this code(s) to come up with what was wrong. Did the dealer give you a sheet with the trouble code number on it?

The engine may have variable valve timing, if it is not working the engine will revert back to a fail safe condition so that no damage will occur. But it will not be running a peak performance. Or it could be something with the engine timing system.

If you want to do your own checking, start calling autoparts stores to see if one will read the trouble codes for free, it is an easy job. AutoZone will read codes for free.

Hope this help.

it is possable that the engine speed sensor failing could resullt in a non starting engine. i would check the fule lift punp in the tank (accessable under rear seats) as thease are comman for failing at around 70000 miles

let me know if this helps
cheers
big mike

This is a common concern with this year model Ford diesel. There are several things to make the truck not start. There is a high-pressure oil sensor on the rear of the passenger side valve cover that if it fails won't let your engine start, there is a cam sensor on the front of the engine that if fails won't let your engine fire. Check all of your fuses and check the injector control module relay in the fuse panel under the hood. There are others that are best handled by ford, there is another high-pressure oil sensor down in the engine valley beneath the intake, the high-volume oil pump could of gone out, a high pressure oil line that if leaks won't let your truck start. the injector control module that if fails the replacement must be programmed to your trucks computer. Ford has a computer specifically designed to work on these trucks and they should beable to check your pump by looking at the oil pressures as it turns over. You can change the cam and the oil sensor on the valve cover yourself but they are expensive around $150.00 a piece and that may not fix it. I recommend taking it to the dealer and letting them looking at it. I know first hand that just throwing parts at it hoping to fix it can get expensive. Hope I was able to help you and answer your questions.

pepboys will read it at no charge

immobiliser cut in dealer only

The normal reason why a hot engine doesn't start is the choke. Your fancy new range rover will have a computer controlled choke that will be activiated by a temperature sensor. maybe this has failed or is disconnected
In my ancient range rover I have a manual choke but essentially the same engine. I know that if the motor is hot I can't start it with the choke on.
The way the choke works is it restricts the airflow into the engine so that there is a richer fuel / air mixture which is needed for a cold start. If the engine is hot and the choke comes on the engiine floods with petrol and there isn't enough oxygen for it too ignite in the cylinders. To start a flooded engine you have to open the choke and crank the motor without pressing the accelerator. This pumps out the petrol vapour and eventually it will fire and start. If the computer thinks it is cold because of a disconnected or faulty sensor it will put on the choke whenever you try and start and the engine will flood.
I think a vapour lock is unlikely unless you driving in extremely hot weather (above 40 degrees celsius).