Hatchback?
If yes, try start car, brake, drive a lil to trigger auto lock. Sometimes the boot latch gets triggers and enabled again. Happened to mine before.

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hi there, i have a 2010 M3 2.0 and having problem almost similar to yours as well.
my mileage 128K, problem as below
1) alarm trigger randomly - change rear lock both side
2) engine light on - clean throttle body & MAF sensor
3) battery weak - change new bat 360+gst
4) rear absorber - advise to change in next service
this bill total 1.3K 

during last service, kocking sound from front suspension when driven on uneven road.
in the end, change front damper, control rod, rubber mounting x 4, bound bumper, done at SC glenmarie, total bill 2.4K  

right now still have rear suspension problem not yet settle.. after change will become like new car?   

Hi, which is the best Mazda service center? I have a sound with my M3 when driving at certain speed, but I went to pj and klang service center but both can't help me to solve it..