Firestone's diagnostic fee is about $100 in 2026
Firestone Complete Auto Care charges roughly $100 for a diagnostic, about one hour of labor. Customers report the fee is credited toward the repair if you have Firestone do the work. Prices vary by store.
What you get for the fee
| What the fee covers | Scanning the codes, targeted testing to find the real cause, and a repair estimate. Firestone is clear that a code read alone is not a diagnosis. |
|---|---|
| Credited if you repair? | Usually, if Firestone does the repair. Confirm with the store when you book. |
| Free code read? | Not at Firestone. Parts stores read codes free; Firestone charges for the diagnosis that follows. |
| Parts pricing | Firestone's part prices tend to be higher than online or independent pricing. The diagnostic fee is fair; compare the repair quote. |
| Store variation | Firestone stores set their own labor rates, so $89 to $130 is all normal. |
| Warranty and coupons | Firestone runs frequent service coupons. Check the store page before booking; diagnostic discounts appear regularly. |
Why the fee exists
Firestone treats the diagnostic fee as one hour of shop labor, which is the industry norm. The company's own service page says the trouble code is the tip of the iceberg and the fee buys the time to test properly. That is accurate. The thing to watch is the repair estimate that follows, not the diagnostic fee itself.
What changes the diagnostic on a Firestone visit
Firestone's diagnostic is a package, not a code read
Firestone Complete Auto Care sells the diagnostic as a check engine light service: a technician pulls the codes, checks freeze frame data, and tests the circuit or component the code points at, billed as roughly one hour of shop labor. The company's own page says the code is the starting point, not the answer, and the fee buys the testing. That is the right description. What you are not paying for is a factory scan tool; Firestone uses aftermarket equipment, which is fine for the engine and emissions faults that make up most check engine visits.
What Firestone credits and what it does not
Firestone stores generally apply the diagnostic charge toward the repair when you approve the work at the same visit, and treat it as a stand alone charge if you take the car elsewhere. Policies are set per store, so confirm at the counter before authorizing. Firestone also runs a free courtesy check (fluids, belts, tires, battery) that is a visual inspection, not a diagnostic; do not confuse the free check with the paid diagnostic when comparing quotes.
Where it fits
Firestone is a good match for a check engine light on a mainstream car out of warranty, a battery or charging complaint, brakes, and anything tire related. It is a poor match for a car under warranty, a fault in a driver assistance system, or a European luxury make, where the store will often read the code and refer you on. The fee is priced like an independent, the hours are longer than most independents, and there is a store in almost every town.
What will my diagnostic cost?
Pick the kind of shop, your state's cost level and how tricky the problem is. The estimate updates as you change them.
Estimates from published 2026 shop rates. Ask the shop for its exact fee before you book.
Common questions
How much is a diagnostic at Firestone?
About $100 in 2026, roughly one hour of labor. Individual stores range from $89 to $130.
Does Firestone waive the diagnostic fee?
Customers consistently report it is credited if Firestone does the repair. Confirm with your store.
Does Firestone read check engine codes for free?
No. The free read is at parts stores. Firestone charges for the full diagnostic.
Is Firestone cheaper than a dealership?
Yes for diagnosis: about $100 versus $150 to $250 at a dealer.