How to Read a Honda OEM Part Number (And Why It Matters)
The 13-character OEM part number is the single most reliable way to confirm you're ordering the right part. Here's how to decode it before you buy — and avoid a costly return.
Every genuine Honda part has an OEM part number stamped on it. That number isn't random — it's a structured code that tells you exactly what the part is, which vehicle it belongs to, and which revision you're looking at. If you've ever ordered what looked like the right alternator only to find it doesn't bolt up, a misread part number is usually why.
Let's break down a real example: 31100-RAA-A01
The Structure of a Honda Part Number
Honda OEM part numbers follow a consistent format with five segments:
| Segment | Example | What It Means |
|---|---|---|
| Part Family Code | 31100 | The category — 31100 means alternator. 31200 = starter motor. 14520 = timing belt tensioner. |
| Vehicle Group Code | RAA | Identifies the engine/platform. RAA = 2.4L K24A iVTEC. RTA = 2.4L K24A. RNA = 1.5L L15A. |
| Revision Code | A | The design iteration. A = original design. B, C = later revisions with engineering changes. |
| Supplier/Spec Code | 01 | Identifies the supplier or specification. Changes when Honda switches suppliers but keeps the same design. |
Key insight: The vehicle group code (middle segment) is the most important for fitment. RAA and RTA look similar but they're different engine variants — swapping them is a common mistake that results in an alternator that physically fits but has the wrong amperage rating.
Common Honda Part Family Codes
Knowing the five-digit family code lets you identify a part instantly without cross-referencing:
| Code | Part Type |
|---|---|
| 31100 | Alternator |
| 31200 | Starter Motor |
| 14400 | Timing Belt |
| 14510 | Timing Belt Tensioner Pulley |
| 14520 | Timing Belt Adjuster / Auto Tensioner |
| 19200 | Water Pump |
| 11810 | Timing Belt Cover (upper) |
| 11820 | Timing Belt Cover (lower) |
Why the Revision Code Matters
Honda revises parts throughout a model run. An Accord built in January 2005 may use a different alternator than one built in October 2007 — even though both are "2005–2007 Accord 2.4L." The revision letter (A, B, C) tells you which generation of the part you need.
In most cases, later revisions supersede earlier ones — Honda publishes supersession tables that tell you an A01 can be replaced by an A02. When in doubt, use the newest revision. Our listings always show the supersession chain in the part numbers table.
How to Find Your OEM Part Number
- Check the old part: The OEM number is usually stamped or labeled on the part itself — on the case of an alternator or on the belt tensioner bracket.
- Use your VIN: Honda's dealer parts system (eStore or a dealer parts counter) can look up your specific VIN and confirm the exact OEM number for your build date.
- Cross-reference our listing: Every product page on CarsAndTrucks.parts includes the OEM part number and all known compatible OEM numbers in the specifications table.
Pro tip: If your original part has been superseded and you can't find the old number, search for the new superseding part number — it will cross-reference back to your application.
Alternative Part Numbers and Cross-References
Many aftermarket manufacturers list their parts using the Honda OEM number as a cross-reference. A Gates timing belt kit, for example, will list 14400-RAA-A01 as a cross-reference even though the Gates part number is something like TCK328. Always verify the OEM cross-reference, not just the brand part number.
Ready to find your part? Use the OEM number from your old component and search our catalog — every listing is indexed by OEM part number for exact-match results.
Popular Parts
Popular catalog lookups include 31200-R40-A01, 31100-R70-A01, 14400-PLM-014, 31100-RAA-A03, plus other high-demand OEM replacement pages below.
31200-R40-A0131100-R70-A0114400-PLM-01431100-RAA-A0319200-RDV-J01104210-124006312-P03-901RM14400-P8A-A02