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 and Pin Connector Angled #5 - 112.5°RedPart 32015Element 6271348 or 4227544×2
Technic Brick 1 x 2 with Axle Hole Type 2 [X Opening]RedPart 32064b×10
Tan
23 pieces
Plate Round 2 x 2 with Axle Hole Type 1 (+ Opening)TanPart 4032aElement 4140562 or 403205×21
Plate Special 1 x 2 with Bar Up [Horizontal Arm 5mm]TanPart 88072Element 6261357 or 4655257×2
Dark Brown
2 pieces
Technic Axle and Pin Connector Angled Triple [120° Offset]Dark BrownPart 10288Element 6273219 or 6005755×2
Orange
2 pieces
Brick and Axle Separator v2.0OrangePart 96874Element 6240515 or 4654448×1
Plate 1 x 2OrangePart 3023Element 4177932 or 4163009×1
Green
1 piece
Plate 1 x 2GreenPart 3023Element 302328×1
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.