Are Car Parts Interchangeable

Are Car Parts Interchangeable

The majority of products manufactured today – vehicles, computers, furniture, toys – use interchangeable parts, meaning easily transferred from one brand or model of a product to another. In fact, the entire concept of mass production depends on interchangeability. One of the most common questions car owners want to know the answer to is: are car parts interchangeable? Is it possible to find replacement parts for your vehicle in a different brand or model? 

The short answer is yes. Auto parts are interchangeable. Not every part and not from every possible car brand and design, but, generally speaking, they can be interchangeable. 

If you’re running an aftermarket parts shop, you can make it easier for your customers to determine whether the parts they’re looking for can be taken from a different make and model. Gone are the salvage yard days – in this modern age, everything is about online catalogs and the convenience of finding the right car part in a matter of a couple of clicks. 

The Importance of Fitment Data

Your online automobile parts business needs a lot to get off the ground. You have to decide on the right business model, the necessary logistics, and which online platform (or platforms) you will use for the actual sales. Some form of marketing also won’t hurt to increase brand awareness. 

However, all of those pale in comparison to the importance of fitment data in your parts catalog. 

Fitment data details where a particular part fits in what vehicle. It can vary by engine size, trim, transmission, model, year, etc. Fitment data determines whether your customers receive the right vehicle part or the wrong one. If your catalog is riddled with errors, customer satisfaction will be low, return rates will be high, and chances of repeat purchases will be non-existent. 

Bad data leads to businesses easily falling behind the competition. 

For interchangeable parts, a fitment table should contain: 

  • Year
  • Make
  • Model
  • Trim/Submodel
  • Engine
  • Vehicle Identification Number (VIN)
  • Part Number, and more

Out of all this information, the VIN and part number are arguably the most significant ones.

VIN and Part Number

VIN is a series of 17 characters (capital letters and numbers) unique for each vehicle. They are essentially a car’s fingerprint – no two vehicles have the same VIN. It contains information about unique features, the manufacturer, and vehicle specifications. 

Vehicles manufactured before 1981 have VINs between 11 and 17 characters. Because of this, information about them may be limited. 

Not every part has its part number, but most of them do. A PN, P/N, part #, or part no. identifies a part beyond a shadow of a doubt within one brand, or perhaps across several brands. Much like the VIN, it contains information about the part type, its dimensions, color, shape, and anything else that might be important. 

Data such as the year, make, and model of a vehicle are required but not specific enough to find a compatible component. VIN and part numbers are essential in narrowing down the search and helping your customers find the right replacement part. 


The good news is that you don’t have to worry too much about the format of your fitment data. 

The Auto Care Association created the Aftermarket Catalog Exchange Standard (ACES) and Product Information Exchange Standard (PIES) to ensure that all car parts data is standardized and high quality. These standards help businesses present their product information in an expected, cohesive manner. 

  • ACES 

The bridge between a part number and a specific vehicle is the ACES standard. It includes all the information mentioned above, such as the vehicle year, make, model, part type, part number, brand, and other fitment data. 

One of the ACES relational databases is the Vehicle Configuration Database (VCdb). It contains around 60,000 vehicle configurations for light, medium, and heavy-duty vehicles sold in the USA, Canada, Chile, Colombia, and Mexico. This database is updated every month, with new vehicle configurations added or old ones eliminated as they enter and exit the market. 

Most automobile aftermarket retailers use ACES as the foundation for their catalogs. It requires a subscription to access and use and thus is not free for all aftermarket businesses. 

  • PIES 

While ACES is centered around application information, PIES handles product data. It contains over 20,000 types of products divided into 25 categories. 

Like the above-mentioned standard, PIES is regularly updated as new information emerges and old data becomes obsolete. PIES does not mandate a subscription, though some databases tied to PIES are only available for a fee. 

ACES and PIES are developed to be used together. An aftermarket retailer can use ACES to decide whether a component fits a specific vehicle and PIES to determine further if that part or accessory meets all their customer’s needs. These standards are invaluable tools in the auto aftermarket industry since they drastically improve online ordering accuracy. 

However, ACES and PIES work only if your product information management system is efficient. Even though they introduce order in the automobile industry and its aftermarket, they are also pretty complex. To help you navigate these standards and provide the best customer experience for your shoppers, you might want to consult a professional who can help validate your product database against the Auto Care standards. 

Catalog Holes

When fitment data is missing from a catalog, this is called a ‘catalog hole.’ If a potential customer tries to find a part or an accessory in the catalog, they won’t get any results. Catalog holes are one of the primary reasons for loss of sales and why it is crucial to keep your fitment database up-to-date. 

A catalog hole usually occurs if a part or an accessory is marked as belonging to a vehicle that has been removed or redefined. In such cases, the component is labeled as invalid, and a customer cannot find it. Additionally, custom-made accessories and parts may not have been entered into any catalog yet. This may require online retailers to enter the custom part information in the database manually. 

One Universal Database

Customers looking for spare parts frequently search for one universal ‘auto parts database’ or ‘auto parts fitment database’ where they can enter information about their part or accessory and get all the relevant information, including compatibility. 

Unfortunately, one giant database containing all of this information doesn’t exist (yet). Instead, every online aftermarket business has its own catalog that (hopefully) meets the ACES and PIES standards. To put your business ahead of the curve, your catalog needs to be comprehensive and include as much information as possible. That way, your customers won’t be compelled to turn to your competitors to find specific parts and their interchangeability data. 


Whether you’re looking for a fender, bumper, engine parts, or something else entirely, the chances are that you can find a part from another vehicle that fits into yours. Questions such as ‘What cars share the same parts?’ are often asked on the internet. 

To establish your businesses as one of the best in the field, your fitment data needs to be accurate and up-to-date. It must include the year, make, model, submodel, engine, part number, VIN, etc. It also needs to be standardized according to ACES and PIES. 

Since there is no one universal fitment database online, your catalog must not have any holes. By continually working on it and keeping it current, you’re creating your customers’ best possible experience. If you have any questions about fitment catalogs or would like some help in managing yours, don’t hesitate to reach out to Illumaware. We would be more than happy to assist you in growing your online aftermarket business!