Rule out the usual hiding places first. If the piece really is gone, check the set piece by piece
and leave with the element ID LEGO asks for, or a link to buy the part.
Technic Axle 3 with StudDark TanPart 6587Element 6031821 or 6013821×3
Technic Axle 5 with StopDark TanPart 15462Element 6055631×3
Pearl Titanium
5 pieces
Large Figure Accessory, Shadow TrapPearl TitaniumPart 24188Element 6135124×2
Large Figure Head, Lower JawPearl TitaniumPart 25528Element 6150531×1
Large Figure Skeletal, Connector with 2 Ball JointsPearl TitaniumPart 24189Element 6139106×1
Large Figure Torso Cover, Armour, RibbedPearl TitaniumPart 20473Element 6122337×1
Flat Silver
4 pieces
Large Figure Accessory, Chain Link SectionFlat SilverPart 53551Element 6124042×4
Pearl Gold
3 pieces
Large Figure Mask of Control with Marbled Trans-Neon Green PatternPearl GoldPart 25532Element 6151004×1
Large Figure Tail / HornPearl GoldPart 87846Element 6145484×2
Tan
1 piece
Technic Pin 3/4TanPart 32002Element 6663097 or 6013938×1
Trans-Neon Orange
1 piece
Large Figure Head Connector Block Eye/Brain Stalk (Toa Okoto)Trans-Neon OrangePart 19050Element 6102640×1
[No Color/Any Color]
1 piece
Sticker Sheet for Set 71316-1[No Color/Any Color]Part 26469Element 6151080×1
Tick each piece as you find it, or mark it missing.
When a piece really is missing
Ask LEGO
LEGO takes requests for pieces missing from a new set through its customer service site. The form asks for
the set number and each piece's element ID, the number printed beside the piece in the parts list at the back
of the instructions. This checker lists both.
Mark a piece missing and your list links it to an eBay search for that part, which also covers pieces from
older or second-hand sets.
Keep a record
Copy or download your missing list (the CSV opens in any spreadsheet), or print the whole checklist and tick
pieces off on paper. Your marks stay in this browser, so you can check a big set over several sittings.