Schreibe es mal so:
ocmd:carlock(playerid,params[])
{
new veh = GetOwnVehicle(playerid);
if(veh == INVALID_VEHICLE_ID) return SendClientMessage(playerid,COLOR_RED,!"Es befindet sich keines deiner Fahrzeuge in der Nähe.");
new engine,lights,alarm,bonnet,boot,objective;
GetVehicleParamsEx(veh,engine,lights,alarm,vehdoor,bonnet,boot,objective);
GameTextForPlayer(playerid, (vehdoor)?("~w~Fahrzeug ~g~aufgeschlossen"):("~w~Fahrzeug ~g~abgeschlossen"), 3000, 5);
SetVehicleParamsEx(veh,engine,lights,alarm,!vehdoor,bonnet,boot,objective);
for(new i; i<MAX_PLAYERS; i++) SetVehicleParamsForPlayer(veh,i,0,!vehdoor);
vehdoor = !vehdoor;
return 1;
}
stock GetOwnVehicle(playerid) {
new t;
for(new i,Float:p[3],Float:tmp=50.0,Float:z; i<sizeof(cInfo); i++) {
if(cInfo[i][besitzer]!=sInfo[playerid][db_id]) continue;
GetVehiclePos(cInfo[i][id_x],p[0],p[1],p[2]);
z = GetPlayerDistanceFromPoint(playerid,p[0],p[1],p[2]);
if(z < tmp) tmp=z,t=i;
}
return (!t)?INVALID_VEHICLE_ID:t;
}
mfg. 
//Edit: Distance 50.0