Vehicle diagnostics is the process of investigating mechanical, electrical and electronic faults using diagnostic equipment, technical information, physical inspections and system testing.

Depending on the symptoms, it may include reading fault codes, examining live data, checking electrical circuits, testing sensors and actuators, inspecting components and confirming communication between control modules.

Not always. A fault code identifies a condition detected by the vehicle, but it does not automatically prove which component has failed. Further testing is often necessary to find the underlying cause.

No. Scanning retrieves information stored by the vehicle. Fault diagnosis involves interpreting that information and completing additional tests to determine why the fault occurred.

No. Scanning retrieves information stored by the vehicle. Fault diagnosis involves interpreting that information and completing additional tests to determine why the fault occurred.

A1 Diagnostics can investigate many engine-management, ABS, airbag, transmission, battery, immobiliser, emissions and driver-assistance warning lights. Capability depends on the vehicle and system concerned.

The light may be triggered by faults involving sensors, wiring, ignition, fuel delivery, emissions equipment, air intake or engine-management systems. Diagnostic testing is required to identify the cause.

This depends on the warning and how the vehicle is behaving. A red warning, flashing engine light, overheating, loss of oil pressure or serious change in performance may require you to stop driving immediately and seek professional advice.

A vehicle may enter reduced-power or limp mode when a control system detects a fault that could affect performance, emissions or component protection. The stored information and vehicle symptoms should be diagnosed before parts are replaced.

Yes, although intermittent faults may require additional testing because the problem might not be present during the initial inspection. Explain when the fault occurs and any conditions that appear to trigger it.

Yes. Electrical diagnosis can involve checking power supplies, grounds, wiring, connectors, battery voltage, communication networks, sensors, actuators and control modules.

Multiple warning lights may be caused by low system voltage, a shared sensor, wiring damage or a communication fault between control modules. They do not necessarily indicate several separate component failures.

Yes. Low or unstable voltage can affect control modules and generate warning messages or communication faults. Battery and charging-system condition may need to be checked during diagnosis.

Yes. A non-starting problem can involve the battery, starter motor, immobiliser, wiring, sensors, fuel delivery, ignition system or control modules. Testing is required to determine the cause.

A1 Diagnostics can investigate many ECU and control-module problems. Diagnosis should also include relevant power supplies, grounds, wiring and communication circuits before a module is declared faulty.

Yes. A1 Diagnostics can investigate many immobiliser, transponder and key-recognition faults. Bring all available keys and proof that you own or are authorised to manage the vehicle.

Yes. Possible causes include wheel-speed sensors, damaged wiring, encoder rings, wheel-bearing faults, hydraulic components or ABS control-system problems.

Yes. A1 Diagnostics can investigate faults affecting supported cameras, radar sensors and driver-assistance systems. The vehicle may require repair, programming or calibration depending on the findings.

In many cases, A1 Diagnostics can complete the required mechanical, electrical, programming or calibration work. The available repair will depend on the fault, vehicle and parts required.

No. Clearing a code removes the stored information but does not correct the underlying problem. If the fault remains, the warning light or code is likely to return.

The cost depends on the vehicle, symptoms and testing required. Straightforward faults may be identified relatively quickly, while intermittent, wiring or communication problems can require more diagnostic time.

Diagnostic time varies according to the complexity of the fault and whether it is present during testing. A1 Diagnostics can explain the initial diagnostic process when you book.

Provide the vehicle registration, mileage, warning messages and a description of the symptoms. Explain when the problem started and whether it followed a repair, flat battery, accident, water ingress or component replacement.

Yes. Previous diagnostic reports, invoices and details of replaced components can help the technicians understand what has already been tested or repaired.

A1 Diagnostics provides diagnostic services for many makes and models of cars and van commercial vehicles. Provide the registration number so the team can confirm compatibility.

A1 Diagnostics has more than 20 years of automotive experience and combines advanced diagnostic equipment with mechanical, electrical, programming and calibration capabilities. The workshop is conveniently located on Sloper Road near Cardiff City Stadium.