Hello.I have a unusual problem... Saturday evening after I finished my work I went to my car unlocked the car and left my backpack in it , locked the car using the key remote button.all good...I returned to my van, finished some paperwork..after I finished,came back to my car... nothing.i couldn't unlock the doors using my remote key button...I did it manually and the car didn't start...I presumed is the key battery was dead.i opened the key, took the battery out and went to a few nearby shops trying to find a battery.i found one,replace it...and nothing.same problems...I brought another battery, hopping the first one was a"new old" battery... nothing...I don't have the 4 digits code...I don't have another key...I presume the sync between immobilizer and the key is gone( kept to long the key without the battery) so I called 2 car locksmiths...they asked me about that code which I don't have...I went back toy car today...I measured the car battery..12.8v..all good...I called AA recovery man.i was hoping he will sync the key with the car but he couldn't.We started the car by bump start...did start alright...soon as I turned the engine off...same problem...I don't know what to do next.i will appreciate any ideas. Thank you