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LEGO Missing Piece Checker

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.

Police Patrol

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4021 Police Patrol

181 pieces in 88 part and color combinations, plus 3 minifigures.

LEGO counts 195 pieces. This inventory comes from a separate parts catalog and lists 196, including the 15 parts inside the minifigures; the two do not always count the same elements, so their totals differ. Spare parts are counted in neither figure.

Before you call it missing

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.

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Piece checklist

Plates 31 pieces

  • Plate 1 x 2 Blue Part 3023 Element 302323 ×1
  • Plate 2 x 2 Corner Blue Part 2420 Element 242073 or 242023 ×2
  • Plate 2 x 6 Light Gray Part 3795 Element 379502 ×2
  • Plate 6 x 10 Light Gray Part 3033 Element 303302 ×2
  • Plate 1 x 2 Red Part 3023 Element 302321 ×3
  • Plate 1 x 4 Red Part 3710 Element 371021 ×2
  • Plate 1 x 6 Red Part 3666 Element 366621 ×1
  • Plate 6 x 8 Red Part 3036 Element 303671 or 303621 ×1
  • Plate 1 x 1 Trans-Dark Blue Part 3024 Element 6513965 or 6252044 ×2
  • Plate 1 x 1 Trans-Green Part 3024 Element 6513967 or 6252046 ×1
  • Plate 1 x 1 Trans-Red Part 3024 Element 6513963 or 6252042 ×1
  • Plate 1 x 1 White Part 3024 Element 6548262 or 302401 ×1
  • Plate 1 x 2 White Part 3023 Element 6552100 or 6548261 ×1
  • Plate 1 x 3 White Part 3623 Element 6552105 or 6550144 ×4
  • Plate 1 x 4 White Part 3710 Element 6552108 or 6548266 ×4
  • Plate 1 x 8 White Part 3460 Element 6550141 or 346001 ×1
  • Plate 2 x 10 White Part 3832 Element 6552109 or 383201 ×2

Bricks 29 pieces

  • Brick 1 x 4 with Bottom Tubes, Lowered Center Cross Support Red Part 3010a ×2
  • Brick 1 x 6 with Bottom Tubes and 2 Lowered Cross Supports Red Part 3009b ×4
  • Brick 1 x 8 with Bottom Tubes and 3 Lowered Cross Supports Red Part 3008b ×2
  • Brick 1 x 1 White Part 3005 Element 6552096 or 6548258 ×2
  • Brick 1 x 2 White Part 3004 Element 6548257 or 4613964 ×4
  • Brick 1 x 3 White Part 3622 Element 6550143 or 362201 ×3
  • Brick 1 x 4 with Bottom Tubes, Lowered Center Cross Support White Part 3010a ×2
  • Brick 1 x 6 with 'POLICE' Thin Black Print White Part 3009bpr0010 ×2
  • Brick 1 x 6 with Bottom Tubes and 2 Lowered Cross Supports White Part 3009b ×5
  • Brick 1 x 8 with Bottom Tubes and 3 Lowered Cross Supports White Part 3008b ×2
  • Brick 2 x 3 White Part 3002 Element 6550133 or 300251 ×1

Hinges, Arms and Turntables 18 pieces

  • Turntable 2 x 2 Plate - Top Light Gray Part 3679 Element 367952 or 367902 ×1
  • Hinge Brick 1 x 2 Base Red Part 3937 Element 393721 ×2
  • Hinge Brick 1 x 2 Top Plate Thin Red Part 3938 Element 6534944 or 6078079 ×2
  • Hinge Tile 1 x 4 White Part 4625 Element 4264365 or 4258048 ×6
  • Hinge Vehicle Roof 4 x 4 White Part 4213 Element 4256454 or 421301 ×2
  • Hinge Vehicle Roof 4 x 4 Sunroof with Ledges White Part 2349b Element 4177755 or 234901 ×4
  • Turntable 2 x 2 Plate, Base White Part 3680 Element 368001 ×1

Plates Round Curved and Dishes 17 pieces

  • Dish 2 x 2 Inverted [Radar] Light Gray Part 4740 Element 474002 ×1
  • Plate Round 1 x 1 with Solid Stud Trans-Dark Blue Part 6141 Element 6514055 or 6240214 1 spare in the box ×4
  • Plate Round 1 x 1 with Solid Stud Trans-Yellow Part 6141 Element 6514056 or 6240216 Also in Yellow ×4
  • Plate Round 1 x 1 with Solid Stud Yellow Part 6141 Element 614124 Also in Trans-Yellow ×8

Bricks Sloped 13 pieces

  • Brick Sloped Inverted 45° 2 x 2 [Ovoid Bottom Pin, Bar-sized Stud Holes] Red Part 3660 Element 366021 ×2
  • Brick Sloped 33° 3 x 4 White Part 3297 Element 329701 ×1
  • Brick Sloped 45° 2 x 2 White Part 3039 Element 6552103 or 303901 ×2
  • Brick Sloped 45° 2 x 2 with Computer Panel Print White Part 3039pr9994 Element 4161154 ×1
  • Brick Sloped 75° 2 x 1 x 3 with Open Stud White Part 4460a ×2
  • Brick Sloped Inverted 45° 2 x 1 White Part 3665 Element 6552106 or 366501 ×4
  • Brick Sloped Inverted 45° 2 x 2 [Ovoid Bottom Pin, Bar-sized Stud Holes] White Part 3660 Element 366001 ×1

Panels 8 pieces

  • Panel 1 x 2 x 1 [Square Corners] White Part 4865a Element 486501 ×6
  • Panel 1 x 2 x 1 with Thin Black POLICE Print White Part 4865apr0002 ×2

Bars, Ladders and Fences 6 pieces

  • Lever Small Base with Black Lever Black Part 298c02 Element 73587 1 spare in the box ×3
  • Bar 1 x 6 [Closed Studs] Red Part 6140 Element 4561802 or 4289557 ×3

Plates Special 6 pieces

  • Plate Special 1 x 1 with Clip Light, Bar Hole [Thick Ring] Light Gray Part 4081b Element 408102 ×1
  • Plate Special 1 x 2 with 1 Stud without Groove (Jumper) Red Part 3794a ×1
  • Plate Special 1 x 1 with Clip Vertical [Thin U Clip] White Part 4085b Element 4542191 ×2
  • Plate Special 1 x 2 with 1 Stud without Groove (Jumper) White Part 3794a ×1
  • Plate Special 1 x 2 with Bar Up [Horizontal Arm 6mm] White Part 4623 Element 462301 ×1

Technic Bricks 6 pieces

  • Technic Brick 1 x 2 [1 Pin Hole] White Part 3700 Element 6619284 or 370001 ×6

Tiles 6 pieces

  • Tile 1 x 2 with Space Computer Print Blue Part 3069bpr0039 ×1
  • Tile 1 x 2 with Video Tape and Reels Print Light Gray Part 3069bpr0020 Element 81466 ×1
  • Tile 1 x 2 with Groove White Part 3069b Element 6548264 or 306901 ×2
  • Tile 1 x 4 with Groove White Part 2431 Element 6548255 or 243101 ×2

Tiles Special 6 pieces

  • Tile Special 1 x 1 with Clip and Straight Tips Black Part 2555 Element 255526 ×1
  • Tile Special 1 x 2 with Handle Black Part 2432 Element 243226 ×1
  • Tile Special 1 x 2 Grille without Bottom Groove Light Gray Part 2412a ×4

Transportation - Sea and Air 6 pieces

  • Boat 38 x 10 x 5 2/3 [Complete Assembly] Black Part 2366c01 ×1
  • Boat, Mast 2 x 2 x 3 Inclined with Stud on Top and Two Sides White Part 4289 Element 6108866 or 4253859 ×1
  • Wing, Tail 4 x 1 x 3 White Part 2340 Element 6347936 or 234024 ×4

Minifig Accessories 4 pieces

  • Equipment Radio [Extended Handle, Compact Speaker Grille] Black Part 3962b Element 396226 ×1
  • Equipment Weapon, Loudhailer / Speaker / Blaster / Space Gun Red Part 4349 Element 434921 ×1
  • Equipment Control Panel White Part 2342 ×1
  • Tap 1 x 1 with Hole in Spout Yellow Part 4599a Element 459924 ×1

Windows and Doors 4 pieces

  • Glass 2 x 3 for Hinge Car Roof 4 x 4 Sunroof with Ridges Trans-Light Blue Part 2348b Element 234842 ×4

Windscreens and Fuselage 4 pieces

  • Windscreen 2 x 4 x 2 Trans-Light Blue Part 3823 Element 6581802 or 6253682 ×2
  • Windscreen 3 x 4 x 1 1/3 with 2 Studs on Top Trans-Light Blue Part 2437 Element 6507914 or 6253361 ×2

Containers 3 pieces

  • Boat Cargo Loading Plate 10 x 12 with 6 x 8 Tub Light Gray Part 2374 ×1
  • Cupboard 2 x 3 x 2 Door Red Part 4533 Element 453321 ×1
  • Cupboard 2 x 3 x 2 with Solid Studs White Part 4532 Element 4258385 or 453201 ×1

String, Bands and Reels 3 pieces

  • String Cord Thin (0.5mm) 50cm Black Part 56823c50 Element 6530026 or 6489925 ×1
  • String Reel 2 x 2 Winch Drum Black Part 2585 Element 4188195 or 4160809 ×1
  • String Reel 2 x 2 Winch Holder Red Part 2584 Element 4188300 or 4161162 ×1

Bricks Round and Cones 2 pieces

  • Cone 1 x 1 [No Top Groove] Trans-Dark Blue Part 4589 Element 618843 ×1
  • Brick Round 1 x 1 Open Stud Yellow Part 3062b Element 306844 or 306224 ×1

Bricks Special 2 pieces

  • Brick Special 2 x 6 x 2 Weight with Sealed Bottom and Dimples on Ends Red Part 73090b Element 74160 ×2

Transportation - Land 2 pieces

  • Steering Stand 1 x 2 with Black Steering Wheel Blue Part 3829c01 Element 9566 ×2

Minifig Headwear 1 piece

  • Helmet, Standard Black Part 2446 Element 6020155 or 4654642 ×1

Minifig Headwear Accessories 1 piece

  • Headwear Accessory Visor For Standard Helmet Trans-Light Blue Part 2447 Element 4652811 or 244742 1 spare in the box ×1

Minifig Neckwear 1 piece

  • Minifig Neckwear Airtanks Yellow Part 3838 Element 4631564 or 383824 ×1

Minifig Shields, Weapons, & Tools 1 piece

  • Weapon Gun / Torch (Space) [with Grooves] White Part 3959 Element 4550643 or 395951 ×1

Stickers 1 piece

  • Sticker Sheet for Set 4021-1 [No Color/Any Color] Part 163175 ×1

Minifigures 3 figures

  • Policeman with Zipper Jacket, White Hat, Life Vest Minifigure, checked as a whole figure ×3

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.

Request a replacement from LEGO

Buy the piece

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.

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