98 Ls400 computer (ecm) problem or key security problem

[Logan pool]

I took my 98 ls400 to a mechanic because the car would not accelerate unless it was completely floored, I had already replaced the throttle position sensor and I took it to the mechanic to replace the acceleration position sensor, after he replaced it and reconnected the battery the car wouldn’t even start anymore and he was getting codes for something like a security problem, and the security light was flashing but if I remember right it has always been flashing. There was also a code for the ECM (computer), I have no idea what the problem is so anything anyone can tell me would help, thank you.

[sha4000]

What codes did the mechanical get from the car? Does the starter spin went trying to start or is there complete silence? Does the horn work? The items that your mechanic replace should not prevent the car from starting but if something is amiss with the security system it would. Make sure the battery is fully charged and that all doors are locked. Then arm the system and make sure the key fob is not within 15 feet. Open the doors and try to start the car.

[Jtate12]

Did you ever solve this?