Car diagnostic test cost UK (2026): scan vs actual diagnosis

Updated 23 July 2026 · OBDCode UK editorial

A basic independent-garage diagnostic assessment typically costs £40–£100; a main-dealer first session is often £90–£180. Ask whether that buys only a code printout or includes testing, live data and a written conclusion.

Typical UK fitted prices in 2026

WorkTypical price
Basic code read/mobile scan£30–£60
Independent diagnostic assessment£40–£100
Complex electrical diagnosis, first 1–2 hours£80–£200
Main-dealer initial session£90–£180
DIY engine code reader£20–£80

These are planning ranges, not quotes. Confirm whether VAT, diagnosis, fluids, calibration and related parts are included.

What changes the price?

  • Coverage: engine-only readers cannot see every ABS, airbag, body or gearbox fault.
  • Time: intermittent wiring and communication faults require logging and pin tests, not a five-minute scan.
  • Brand tooling: coding, calibration and guided tests can require manufacturer-level access.
  • Fee policy: some garages deduct diagnosis from repair; others charge it separately.

Confirm the fault before authorising the job

Request the actual code numbers, freeze-frame conditions and tests that prove the recommended part failed. A code names the circuit or symptom detected, not automatically the component to buy.

How to compare quotes like-for-like

Compare scope: modules scanned, included labour time, road test, smoke/pressure/electrical tests and whether a report is supplied. “Free diagnostics” often means only a sales-led code read.

Tools that help with this check

Frequently asked questions

Will a diagnostic test tell me exactly what is wrong?

Sometimes, but not from the code alone. A good technician confirms power, ground, signals, live data and mechanical causes before naming a part.

Is it worth buying an OBD2 scanner?

For engine warning lights and repeat use, a reader can pay for itself. ABS, airbag, DPF and service functions require the right full-system coverage.

Sources and further reading

General guidance for UK drivers, not professional advice. MOT rules follow the DVSA inspection manual (2026 edition).