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 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
Technic Pin 3/4TanPart 32002Element 6663097 or 60139381 spare in the box×2
Lime
15 pieces
Plate 1 x 2LimePart 3023Element 4164037 or 4122439×2
Plate 1 x 3LimePart 3623Element 4534664 or 4271564×1
Technic Axle and Pin Connector Perpendicular 3L with 2 Pin HolesLimePart 42003Element 6273728 or 6211876×10
Technic Pin Connector Round 1L [Beam]LimePart 18654Element 63027411 spare in the box×2
Reddish Brown
7 pieces
Technic Axle 3 with StopReddish BrownPart 24316Element 6135494×4
Technic Axle 5 with StopReddish BrownPart 15462Element 6159763×3
Trans-Clear
6 pieces
Brick Curved 2 x 1 No Studs [1/2 Bow]Trans-ClearPart 11477Element 6508253×2
Plate 1 x 1Trans-ClearPart 3024Element 6513962 or 62520411 spare in the box×2
Technic Panel Fairing #7 3L Very Small Smooth, Side ATrans-ClearPart 2387Element 6510993Also in White×1
Technic Panel Fairing #8 3L Very Small Smooth, Side BTrans-ClearPart 2389Element 6513876 or 6426596Also in White×1
Dark Tan
5 pieces
Technic Axle 3 with StudDark TanPart 6587Element 6031821 or 6013821×2
Technic Axle 4.5 with StopDark TanPart 7784Element 6569661×3
Orange
5 pieces
Technic Pin Long with Friction Ridges Lengthwise and Stop Bush [2 Lateral Holes, Small Pin Hole]OrangePart 65304Element 6347790×5
Dark Blue
2 pieces
Technic Axle 3.5 with StopDark BluePart 8168Element 6601618×2
Medium Azure
1 piece
Plate 1 x 4Medium AzurePart 3710Element 6603965 or 6070757×1
[No Color/Any Color]
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.