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.
Builders who report a missing piece often find it in one of these places. Tick each one off as you look.
Look-alike colors in this set
These parts appear in this set in two colors that are easy to confuse. If you are one short in one color,
check whether it went in where the other color belongs. Each color has its own element ID in the parts list
at the back of the instructions.
Technic Panel Fairing #7 3L Very Small Smooth, Side AWhite ×8Trans-Clear ×1Trans-Clear is see-through: hold the piece up to a light.
Technic Panel Fairing #8 3L Very Small Smooth, Side BWhite ×8Trans-Clear ×1Trans-Clear is see-through: hold the piece up to a light.
Technic Panel Fairing 2 x 1 x 1Black ×1Dark Bluish Gray ×6Black is darker than Dark Bluish Gray.
Technic Panel Fairing 2 x 3 x 1Black ×8Dark Bluish Gray ×2Black is darker than Dark Bluish Gray.
Tile Round 1 x 1Black ×2Dark Bluish Gray ×10Black is darker than Dark Bluish Gray.
Technic Gear Differential with Inner Tabs and Closed Center, 28 Bevel Teeth [Beveled Edge]Dark Bluish GrayPart 62821bElement 4562210 or 4525184×1
Technic Gear 12 Tooth BevelTanPart 6589Element 4565452 or 4514556×5
Technic Gear 20 Tooth Double Bevel with Axle Hole Type 1 [+ Opening]TanPart 18575Element 6346517 or 6084724×1
Tiles Round and Curved
12 pieces
Tile Round 1 x 1BlackPart 98138Element 6284070 or 61394031 spare in the boxAlso in Dark Bluish Gray×2
Tile Round 1 x 1Dark Bluish GrayPart 98138Element 6284596 or 62224161 spare in the boxAlso in Black×10
Technic Beams Special
10 pieces
Technic Beam 1 x 2 with Axle on SideBlackPart 7244Element 6542617×4
Technic Beam 2 x 3 Thick [90° Offset Centre Beam Hole]Dark Bluish GrayPart 3167Element 6475314×2
Technic Beam Frame 5 x 7 with 3 x 5 Opening ThickLight Bluish GrayPart 64179Element 4539880×2
Technic Link 1 x 6 x 2 Angled, Bent, DoubleWhitePart 7684Element 6601523×2
Wheels and Tyres
8 pieces
Tyre 43.2 x 14BlackPart 30699Element 6518575 or 6182551×2
Tyre 43.2 x 22 ZRBlackPart 44309Element 4184286×2
Wheel 30 x 14BlackPart 56904Element 6251174×2
Wheel 30.4 x 20 without Pinholes, with Reinforced RimBlackPart 56145Element 4299389 or 4284946×2
Tiles
7 pieces
Tile 1 x 2 with GrooveBlackPart 3069bElement 306926×1
Tile 1 x 3BlackPart 63864Element 4558170×1
Tile 2 x 2 with GrooveBlackPart 3068bElement 306826×2
Tile 1 x 1 with GrooveBluePart 3070bElement 4206330 or 3070731 spare in the box×2
Tile 1 x 1 with GrooveWhitePart 3070bElement 6550138 or 3070011 spare in the box×1
Bricks Curved
6 pieces
Brick Curved 2 x 2 x 2/3BlackPart 15068Element 6053077×2
Brick Curved 2 x 1 No Studs [1/2 Bow]Trans-ClearPart 11477Element 6508253×2
Brick Curved 4 x 1 No Studs [Stud Holder with Symmetric Ridges]WhitePart 11153Element 6578744 or 6564905×2
Technic Bricks
5 pieces
Technic Brick 1 x 1 with Axle HoleLight Bluish GrayPart 73230Element 6336539×5
Bars, Ladders and Fences
2 pieces
Bar 3LWhitePart 87994Element 6552205 or 64288031 spare in the box×2
Bricks Sloped
2 pieces
Brick Sloped 30° 1 x 1 x 2/3 (Cheese Slope)WhitePart 54200Element 6550179 or 45043691 spare in the box×2
Plates Round Curved and Dishes
2 pieces
Plate Round 1 x 1 with Solid StudWhitePart 6141Element 6601919 or 6141011 spare in the box×2
Plates Special
2 pieces
Bracket 1 x 1 - 1 x 1 InvertedWhitePart 36840Element 6548290 or 6242241×2
Tiles Special
2 pieces
Tile Special 1 x 1 with Clip with Rounded EdgesWhitePart 15712Element 6348055 or 6054551×2
Stickers
1 piece
Sticker Sheet for Set 42234-1[No Color/Any Color]Part 10122231Element 6667759×1
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.