Caterpillar PIN Decoder: CAT Serial Number Lookup Guide
Last updated · 9 min read
Quick answer
A modern Caterpillar PIN is 17 characters following ISO 3779. Positions 1–3 identify the plant (WMI), 4–8 the product family and configuration, 9 a check digit, 10 the model-year letter, 11 the sub-plant, and 12–17 the serial sequence. Pre-2001 Caterpillar machines use a legacy 8-character serial — a 3-letter model-and-plant prefix plus a 5-digit sequence (e.g. AKM00347).
What each position of a modern Caterpillar PIN means
Caterpillar PINs (Product Identification Numbers) on equipment built since approximately 2001 follow the international VIN standard, ISO 3779. The 17 characters split into six functional fields:
| Pos. | Field | Meaning | Example |
|---|---|---|---|
| 1–3 | WMI (World Manufacturer Identifier) | Identifies the manufacturer and the assembly plant. Caterpillar uses multiple WMIs depending on the plant of origin and product line. | CAT = Caterpillar US plants (Aurora, IL; East Peoria, IL; Decatur, IL); CAB = Caterpillar Belgium (Gosselies — wheel loaders, articulated trucks); CAJ = Caterpillar Japan (Akashi — mini and mid excavators); 0HK = Caterpillar UK (Desford — backhoes and small wheel loaders). |
| 4–8 | VDS (Vehicle/Product Descriptor Section) | Encodes the product family, model series, and configuration — boom type, undercarriage, engine tier, cab variant. The exact mapping is Caterpillar-internal and varies by product line. | On a 320 hydraulic excavator the VDS distinguishes 320, 320GC, 320D2 and 323; on a 950 wheel loader it distinguishes 950M, 950GC, 950 XE and the high-lift configurations. |
| 9 | Check digit | ISO 3779 check digit calculated from the other 16 characters. A wrong check digit means the PIN was mistyped or fabricated — a primary fraud signal on a re-stamped plate. | Numeric 0–9 or letter X (representing value 10). |
| 10 | Model-year code | A single letter or digit indicating the model year. ISO calendars skip I, O, Q, U and Z. The cycle repeats every 30 years (so K could mean 1989 or 2019); the WMI and serial-sequence range disambiguate. | M=2021, N=2022, P=2023, R=2024, S=2025, T=2026, V=2027. |
| 11 | Plant / line code | Sub-plant code identifying the specific assembly line within the WMI plant. Often overlaps with — and refines — the legacy 3-letter prefix. | On Gosselies-built articulated trucks, position 11 separates the dedicated 740/745 line from the wheel-loader line that shares the WMI. |
| 12–17 | Serial sequence | Sequential build number for the model year and plant combination. 6 characters, zero-padded. On most modern Caterpillar PINs, the last five characters of this field replicate the legacy 5-digit serial sequence. | 012345 = the 12,345th unit off that model-year line. |
Model-year letter table (position 10)
ISO 3779 uses single characters for model year, skipping I, O, Q, U, and Z (to avoid confusion with digits and other letters). The letter cycle repeats every 30 years; reading the WMI and the serial-sequence range will disambiguate which decade you're in.
| Letter | Model year (2010s) | Model year (2040s) |
|---|---|---|
| A | 2010 | 2040 |
| B | 2011 | 2041 |
| C | 2012 | 2042 |
| D | 2013 | 2043 |
| E | 2014 | 2044 |
| F | 2015 | 2045 |
| G | 2016 | 2046 |
| H | 2017 | 2047 |
| J | 2018 | 2048 |
| K | 2019 | 2049 |
| L | 2020 | 2050 |
| M | 2021 | — |
| N | 2022 | — |
| P | 2023 | — |
| R | 2024 | — |
| S | 2025 | — |
| T | 2026 | — |
| V | 2027 | — |
| W | 2028 | — |
| X | 2029 | — |
| Y | 2030 | — |
Earlier letters (A–Y, 1–9) are reused on the same 30-year cycle. Letters skipped throughout: I, O, Q, U, Z.
Common Caterpillar 3-letter prefix codes (legacy 8-character serials)
On pre-2001 Caterpillar equipment, the serial number is 8 characters: a 3-letter model-and-plant prefix followed by a 5-digit sequence. The 3-letter prefix is the model identifier — when the data plate or operator's manual is missing, this is the field that recovers the model family. A representative subset:
| Prefix | Model family | Notes |
|---|---|---|
| AKM | D6 dozer (mid-1990s era) | Classic 3-letter prefix used on track-type tractors of the D6 family in the late legacy-serial era. Expect a plant-of-origin tie to East Peoria. |
| 8JC | D9 dozer (legacy track-type tractor) | Used on D9L / D9N era large dozers. East Peoria production. Look for it cross-stamped on the main frame near the front idler. |
| GBJ | 320D hydraulic excavator | One of several 320-family prefixes; Akashi / Sagami plant origin. The 320 family also uses prefixes such as PHX (320D2) and LBG depending on year and option. |
| JJG | 950 / 950G wheel loader | Aurora, Illinois production. The 950 family rolls through several prefixes (CYC, BXY, etc.) across generations. |
| B1P | 740 articulated dump truck | Peterlee, UK era prefix for the 740 articulated truck family before consolidation onto the modern 17-character format. |
| BXJ | 966 wheel loader | Used on 966G / 966H wheel loaders out of Aurora, IL. Cross-check the prefix against the model decal on the loader-arm boss — they should agree. |
| CFP | 416 backhoe loader | Backhoe-loader prefix from the Desford, UK plant — the historical home of CAT backhoes. The PIN plate sits on the cab pillar or dash on this family. |
| DGT | D8 dozer (D8R / D8T era) | Large track-type tractor prefix; East Peoria. Frame-stamp position is on the main case behind the right track frame. |
| ASW | 262 / 272 skid-steer & compact-track loader | Compact-equipment prefix from the Sanford, NC compact-equipment plant. PIN plate location differs from the big-iron convention — see the find-the-plate section below. |
| RNB | 330 hydraulic excavator (330 / 330L family) | Excavator prefix from the Akashi plant for the 330 mid-large excavator family. Modern 330 PINs migrated to the 17-character ISO format from approximately 2001 onward. |
Caterpillar has used several thousand distinct legacy prefixes across its product history. The Machinetrail lookup resolves any prefix in our 2.4M-decoded-PIN corpus, including the long tail.
Common Caterpillar WMI codes (positions 1–3)
- CAT — Caterpillar US plants. Aurora, IL (wheel loaders), East Peoria, IL (track-type tractors and large excavators), Decatur, IL (mining trucks).
- CAB — Caterpillar Belgium, Gosselies. Wheel loaders and articulated trucks (740, 745).
- CAJ — Caterpillar Japan, Akashi. Mid-size hydraulic excavators (320, 323, 330) and the joint-venture mini line.
- 0HK — Caterpillar UK, Desford. Backhoe loaders (416/420/430) and small wheel loaders.
- CAS — Caterpillar France, Grenoble / Rantigny. Specialty equipment and historical excavator production.
- CSX — Caterpillar compact equipment, Sanford, NC. Skid-steers, compact-track loaders, mini-hydraulic excavators.
Where to find the serial plate on a Caterpillar machine
- Hydraulic excavators (320, 330, 336, 349):right-hand side of the operator-cab base, near the cab door step. The plate is riveted to the lower cab structure and carries the full 17-character PIN plus the model designation. Caterpillar also cross-stamps the serial into the machine's main frame on the right-hand side of the upper revolving structure.
- Wheel loaders (950, 966, 980, 988): right-hand side of the cab base, sometimes on the front of the operator platform near the access steps. The frame-stamp is on the rear-frame casting near the articulation joint.
- Backhoe loaders (416, 420, 430, 450): on the dash console inside the cab or on the right-hand cab pillar. Older Desford-built backhoes carry the plate on the loader-arm tower as well.
- Track-type tractors / dozers (D6, D8, D9, D10, D11): on the chassis frame near the front of the machine, typically on the right-hand side near the equalizer bar or the front idler. Cross-stamped on the main case behind the right track frame.
- Articulated trucks (725, 730, 740, 745): on the front of the cab on the right-hand side, with a cross-stamp on the front-frame casting between the cab and the engine bay.
- Compact equipment (skid-steers, CTLs, mini excavators): inside the cab on the rear bulkhead behind the operator seat, or under the seat on the smallest machines.
- Engine serial (separate).Stamped on the engine block — typically on the right-hand side of the cylinder block next to the engine data plate. This identifies the engine, not the chassis. On a re-powered machine the engine serial will not match the factory chassis-PIN-implied engine; that's normal but worth recording.
Always cross-check the riveted plate against the engraved frame stamp. A missing or freshly painted plate, or a plate-vs-frame mismatch, is the single most reliable stolen-equipment signal at the inspection stage.
Reading a legacy 8-character Caterpillar serial
For pre-2001 Caterpillar equipment the position-by-position table above does not apply. The legacy 8-character serial is structured as:
- Characters 1–3: alphabetic model-and-plant prefix (e.g. AKM, 8JC, GBJ). This identifies the model family and the plant of origin.
- Characters 4–8: 5-digit sequential serial number (e.g. 00347), zero-padded.
There is no positional model-year code on a legacy serial — the year is inferred from the prefix-and-serial-range tables Caterpillar dealers maintain, and from the cross-stamped manufacture date that appears on the data plate alongside the serial. Some 2000–2002 transition machines carry both a legacy serial and a modern PIN on the same plate; in that case the modern 17-character PIN is the one to use for any post-2001 registry, parts, or dealer lookup.
Caterpillar telematics: Cat Vision Link, Cat App, and PSR
On enrolled machines, Caterpillar maintains its own telematics and dealer-service data layer. Cat Vision Link and the consumer-facing Cat App expose hours, location, fault codes, and fuel burn for fleets that have opted in. Authorized Cat dealers can also pull the Product Service Report (PSR) — a per-PIN history of dealer-touched maintenance events. Neither layer is a public registry: enrolment is owner-controlled, and PSR access is dealer-mediated. For an arm's-length pre-purchase check on a used machine you don't yet own, those CAT-internal layers are typically unavailable, which is why an independent multi-registry lookup matters.
What to do once you've decoded the PIN
A correct decode is just the structural-validity check — it confirms the PIN is well-formed and resolves to a real configuration. The pre-purchase value comes from cross-referencing that PIN against three failure-mode databases:
- Stolen-equipment registries. NER (US), TER-Europe (UK/EU), and the 14 European registries Machinetrail queries in a single lookup against a 1.7M-record stolen-equipment dataset. A stolen Cat will be reclaimed by police regardless of how clean the paperwork looks.
- Open safety recalls. EU Safety Gate, member-state agencies, and OEM recall feeds covering 4,700+ EU machinery recalls. Open recalls on hydraulic, brake, or undercarriage systems are a measurable safety risk and a re-sale-value problem.
- Auction comparables and market value. What did similar machines actually sell for in the last 12 months? Decoded PIN + model + year + hours + region returns the range of recent sale prices.
All three are bundled into the €19.99 Machinetrail standard report; the free preview surfaces the recall count, top-5 known issues, and two recent auction prices. A €49.99 premium tier is coming soon for fleet buyers and dealer use.
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