Diagnostic Fees at the Dealership: What It Is and When to Pay It

A diagnostic test occurs when a technician connects a scanning device with a car’s engine control unit (ECU), often referred to as the “computer” or brains of the vehicle. The scanning device talks to the ECU, pulling reports on any issues or anomalies during operation. Like virus-scanning software, diagnostic tests scan for bugs in the various systems that make your car run. If the computer detects an issue, it makes a log of the problem for reference. 

Diagnostic tests check various components of your vehicle, including: 

• Powertrain
• Throttle
• Brakes 
• Various sensors
• Exhaust system
• Fuel system
• Advanced safety systems

Most people first experience the process of a diagnostic test when their vehicle illuminates a dashboard warning light. Technicians must use their scanning tools to retrieve information on why the light came on. Diagnostic tests can save money if you catch the issue early on. A minor issue detected by a diagnostic test could save you the cost of a brand-new engine or transmission. 

What does a diagnostic fee cover?

At their core, diagnostic fees cover the time an automotive technician spends decoding the reports the ECU records. It’s the same reason you pay a lawyer or personal trainer an hourly rate. The fees are representative of expertise as much as they are of the time spent focusing on the problem at hand. However, diagnostic fees do not cover repairs. 

If, for example, you notice a check engine light come on in your lease vehicle, you should visit the dealership as soon as possible. Your lease agreement will stipulate who is responsible for repairs on a leased car, but most leasing companies require an official diagnosis from an approved service center (a dealership). The leasing company may ask the dealership to forward them the bill for any diagnostic fees unless it was determined that you were at fault and liable for the check engine light coming on. 

Dealerships also charge fees because you could have them diagnose the issue at the standard hourly rate and then find a repair shop that would charge less. Arguably, the dealership did the work to diagnose the problem but missed the chance to profit from that discovery. However, you have no obligation to pay the dealership to fix any issues, even if they did help you figure out the underlying problem. 

Is a diagnostic fee mandatory at all dealerships?

Dealerships may not require diagnostics before assessing a problem, depending on your car’s particular issue. Diagnostics are typically done when the cause of an issue is unknown. For example, your vehicle may require diagnostics if there is an unexplained leak, noise, or group of symptoms that don’t necessarily lead to a single source. For anything electrical, diagnostics can often expedite identifying and addressing these issues.

Do dealerships deduct the diagnostic fee from repair costs?

Deducting diagnostic fees from the final repair bill is an individual choice many dealers make, similar to policies that allow car dealerships to be open on Sundays. While it’s not a requirement for dealerships to apply your diagnostic fees to your overall service bill, many observe this practice. It’s part and parcel of good customer service, especially when customers can easily take a diagnosis and seek out cheaper labor instead.  

The exception to this rule would be a situation where the issues at hand fall under warranty, whether a manufacturer’s or extended warranty. Dealerships may not immediately cover all or a portion of the diagnostic fees until the warranty claim has been verified. Should the repair fall under warranty work, the dealership will handle any fees and paperwork accordingly.

The average diagnostic fee at a dealership can range from $40 to $60 on the low end or $100 to $400+ on the high end. Most dealerships equate the diagnostic fee to one hour of labor. As you might expect, more expensive brands like BMW and Land Rover have a higher hourly rate than Honda or Ford. Diagnostic fees also vary based on location and don’t include taxes. 

In addition to an hourly rate, dealerships may limit the time a technician spends investigating an issue and the diagnostic fee you pay. When you sign the paperwork authorizing the dealership to investigate your concern, the service writer will typically explain to you that they’re capping the investigation off at an hour (which corresponds to a flat diagnostic fee) or that the technician will spend up to a certain amount of time on the issue, which is subject to the hourly labor rate. Read the fine print before you sign to understand what fees you’re liable for before work begins. 

It’s important to note that diagnostic fees are not associated with your car insurance. Diagnostics exist within the realm of maintenance and repairs, so you don’t have to worry about filing a claim or involving your insurance if your car needs diagnostics. 

Most expensive diagnostic fee at a dealership by brand

Per RepairPal, these are the estimated costs of diagnostics at various dealerships by brand: 

Brands within the same dealership group (Chevrolet, Buick, and GMC, for example) typically have similar diagnostic fees. However, you can expect luxury variants (such as Nissan’s INFINITI brand) to charge slightly more for diagnostics. 

Spending $100 to determine what is wrong with your car is a lot of money. If you want to avoid paying this fee and dealing with maintenance, check out a FINN car subscription. Your monthly payment includes maintenance, registration, insurance, and depreciation. With FINN, you can pick which vehicle you want to drive, select your subscription terms, and pay for fuel to get you wherever you want to go. 

When you visit the dealership, you can also request a multi-point inspection before authorizing a diagnosis. Sometimes, these inspections reveal the issue without hooking up any equipment. However, many dealerships may include this inspection as part of the first hour of labor they charge for diagnostics, so you might be on the hook for a diagnostic fee either way. 

Tips for saving on diagnostic fees

Many people don’t realize that you can visit your local auto parts store to have your vehicle’s dash lights checked. A customer service representative will plug a scanner into your car’s OBD II port to read the codes stored within the onboard computer. While these auto parts stores may not be able to service your vehicle directly, they can help you narrow down the issue without paying a costly diagnostic fee. 

In addition, you can also purchase your own OBD II scanning tool. These scanners are available in varying price ranges, with the most sophisticated ones topping out at a few thousand dollars. However, most people don’t have the training or knowledge necessary for decoding what the scanner tells you. In these instances, it pays to visit a dealership where a certified technician can assist. 

The value of paying for diagnostic fees varies on a case-by-case basis. Paying diagnostic fees can help technicians quickly assess the situation, but time is money. However, this discussion is also similar to one regarding what credit score is necessary to buy a car. It’s better to have the highest score possible to pay less in interest, but that doesn’t mean you should (or can) wait until your score is the highest it will ever be. 

Instead, it’s about taking stock of the situation and figuring out what’s best for you. Paying a diagnostic fee now can help you identify issues before they become costly problems, depending on what’s happening. If you can live with the car not being perfect (i.e., hearing the occasional noise), you don’t need to worry about diagnostic fees until the problem worsens. 

When you subscribe to a car with FINN, maintenance is included in your monthly price. You don’t have to worry about making dealership appointments or diagnostic fees. Instead, your car subscription can be delivered to your door every six to 12 months. Your FINN car subscription also includes insurance, depreciation, and registration to maximize the benefits of driving without the burdens of car ownership.