Vehicle diagnostics

Find out what is behind the fault.

Diagnostics combines electronic fault-code readings with inspections and component testing. The aim is to understand the cause of the problem and discuss the repair it needs.

• Dashboard warning lights and stored fault codes.
• Changes in engine power or running.
• Intermittent faults and unusual noises.
• Component checks to investigate the symptoms.

A fault code is the start of the investigation

A diagnostic scan can identify a fault recorded by a vehicle's control systems. It does not, on its own, prove which part needs replacing. The symptoms, inspections and relevant component checks help the workshop understand what is happening before a repair is discussed.

Intermittent problems can be difficult to reproduce. Details such as whether the engine was cold, the length of the journey and when a warning appeared can be more useful than a guess at the cause. A photo of a dashboard message can also help you explain it.

Tell us what has changed

Mention recent repairs, a flat battery, difficult starting, loss of power or changes in fuel use. If another garage has already carried out tests, bring the report rather than relying on a remembered code. This gives the team a clearer starting point.

If you are unsure whether the vehicle should be driven, call before setting off and describe the warning or symptoms. The booking form is for arranging a workshop discussion and is not monitored as a roadside assistance service.

Intermittent faults need a good description

A problem that disappears before the appointment can be difficult to reproduce. Note whether it happens from a cold start, in wet weather, after a longer journey or with a particular electrical item switched on. A passenger can record a message or noise when it is safe; do not use a phone while driving.

The exact wording of a dashboard message can be more useful than a general description such as “engine problem”. Tell the workshop if the battery has recently gone flat, if parts have been fitted or if fault codes have already been cleared. Previous reports can help put the current symptoms in context.

Agree the investigation before the repair

A scan may identify the system reporting a fault without proving which part has failed. The next step can involve checking wiring, connections, operating data or the component itself. Ask what the initial diagnostic charge covers and whether further investigation would need approval.

Once there are findings, ask the team to explain the likely cause, the proposed work and any uncertainty that remains. Diagnosis and repair are different stages: a request for a diagnostic appointment is not an instruction to replace every component mentioned in a fault-code list.

Useful details to have ready.

Tell us when the problem happens: starting from cold, once the engine is warm, while braking or at a particular speed. Mention any work already carried out.

• Your registration, make and model.
• Your mileage and the work you’d like to discuss.
• Any warning lights, noises or changes you’ve noticed.
• Your preferred day and a number to reach you on.

The branch will confirm the work and a suitable time with you. Sending a request does not book a workshop slot.