Diagnostics and Tuning in Ogies

About diagnostics and tuning

A diagnostic scan reads the fault codes stored by the car's control modules, but a code is a clue, not a diagnosis. A code pointing at an oxygen sensor often means the sensor is reporting a real problem elsewhere, such as an air leak or a failing injector. Good diagnostic work uses live data, freeze frame information and physical testing to confirm the cause before any part is bought. Expect to pay for diagnostic time, and expect a workshop that charges for it to be more thorough than one that offers a free scan and then sells parts. Tuning is a separate service. A remap adjusts fuelling and boost for more power or better economy, and on a healthy modern turbo engine the gains are real, but a bad map shortens the life of the clutch, gearbox and turbo. Ask whether the tuner keeps a copy of the original file, and tell your insurer, because an undeclared modification can affect a claim.