Bitrix\Main\Loader::includeModule('iblock');
use \Bitrix\Iblock\ElementTable;
$res = ElementTable::getByPrimary([
'filter' => ['IBLOCK.CODE' => 'ads',],
'select' => ['ID', 'NAME','PROPERTY_GARAGE']
]);
\Bitrix\Iblock\Elements\ElementCatalogTable::getList([
"select" => [
"ID", "NAME",
"BRAND_VALUE" => "BRAND.VALUE",//BRAND - это символьный код свойства
]
])