What does a car diagnostic cost?
A diagnostic charge is technician time, not a machine reading. Understanding that is most of what you need to judge whether a quote is fair — and whether the cheaper option is actually the same thing.
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- 1Describe the repair
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- 3Compare the offers
What changes the price
We do not publish an average price: we do not yet have enough real data to give an honest one. Here is what makes up the bill instead.
- How long it takes to find the cause
- The charge is usually a block of labour — often around an hour, sometimes more for an intermittent fault. A problem that only appears when the engine is cold, or once a week, costs more to find because it has to be caught happening.
- What kind of fault it is
- A stored code pointing at one sensor is quick. A misfire, an electrical fault, a noise, or a leak that only shows under load are all work. The same fee does not cover every case.
- Whether it is credited against the repair
- Some garages deduct the diagnostic fee if you go on to have the work done there. Many do not. This is one of the most worthwhile things to ask before you agree, and one of the most common differences between two quotes.
- The shop rate
- Because it is labour, it scales with what the garage charges per hour — which is why the same diagnosis differs between a dealer and an independent shop.
A free code read is not a diagnosis
A parts store pulling a code from your car tells you which system reported a problem. It does not tell you which component failed or why. A code for a lean mixture can be a leak, a sensor, a pump or an injector — a diagnosis is the work of narrowing that down, and it is the part you are paying a garage for.
Why a garage may refuse to quote before diagnosing
Because a price for the wrong repair is worthless to both of you. When a symptom has several plausible causes, the honest sequence is diagnose, then quote. A garage that gives you a confident figure for an undiagnosed noise is guessing.
What you get for the fee
Ask what you receive at the end: the cause, what is needed to fix it, and a quote for that work. A diagnosis that produces only a code number has not given you much.
What a garage needs to know
- The year, make and model
- What the car is doing, and when — cold, hot, at speed, idling
- Whether a warning light is on, and whether it is steady or flashing
- Any codes you already have, if somebody has read them
- Whether it happens every time or occasionally
When an inspection is needed
If a warning light is flashing rather than steady, or the car is running badly, that is usually treated as something to stop driving and have looked at. This page cannot tell you what is wrong with your vehicle.
How it works
- 1
Tell us what your vehicle needs
One request, a few minutes.
- 2
We look for garages able to perform the work
We contact garages in your area.
- 3
Compare the offers you receive
Price and availability, side by side.
- 4
Choose the option you prefer
You are free to walk away.
Common questions
Will the diagnostic fee come off the repair?
Sometimes. It is a garage-by-garage policy rather than a rule, so it is worth asking directly when you get the quote. It can be the difference between two otherwise similar offers.
Why not just replace the part the code points at?
Because a code names the system that noticed a problem, not always the part that caused it. Replacing the named sensor when the real fault is upstream means paying twice — once for the wrong part and again for the diagnosis you skipped.
Can you tell me what is wrong from my description?
No, and neither can any website. What we can do is get your description in front of garages near you so they can tell you what they would charge to find out.
Why is there no average price here?
Because it would be invented. We have no body of quote data to average yet, and an average across the country would be wrong for your vehicle in your city anyway. Real quotes for your actual car are worth more than a number nobody can defend.
If you do not yet know what the repair is, a diagnosis is the right first purchase. Describe the symptom and garages near you can quote you for finding the cause.
What we don't promise
We don't guarantee a number of offers, a response time, or a saving. We pass your request to garages and show you what they say. If nothing comes back, we'll tell you.
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