Vehicle Engine Diagnostic Test

On-board diagnostic systems function by interpreting error codes generated by a vehicle’s internal computer network. Most modern vehicles are equipped with several onboard computers called Electronic or Engine Control Units (ECUs) that constantly monitor performance and automatically detect faults. These systems are also commonly referred to as ‘Engine Management Systems’ (EMS), ‘Engine Control Modules’ (ECM) or ‘Electronic Control Modules’.

Sensors located throughout the vehicle send feedback to the ECU when issues arise, such as low fluid levels or rising engine temperatures. When a fault is detected, the ECU creates an error code and triggers a dashboard warning light. Without the correct diagnostic equipment these codes can be difficult to interpret. At ESP Servicing, Bosch OBD II scanners are used to retrieve and analyse these codes, helping identify the underlying issue.

There are hundreds of potential OBD2 error codes that require specialised diagnostic tools to read accurately. While a dashboard light may alert you to a fault, a proper on-board diagnostic check is required to understand the cause and determine whether further investigation by a technician is needed.

Bosch OBD II diagnostic tools can also reset service lights, test and calibrate braking systems equipped with electronic handbrakes, and adjust headlamp alignment. For further information, contact ESP Servicing.

Considering that the average cost of an on-board diagnostic check ranges between £50 and £100, and that it can quickly identify faults affecting your engine or other critical components, it is often a worthwhile investment. A diagnostic scan may even reveal issues before a warning light appears on the dashboard.

Dashboard warning lights are indicators on your vehicle’s instrument panel designed to notify drivers about possible faults or system alerts. They can range from simple reminders like low fuel or an unfastened seatbelt to serious warnings such as engine overheating, oil pressure problems, or brake system faults.

For examples of common dashboard warning lights and their meanings, visit our What Do Your Dashboard Warning Lights Mean? page

One of the most important dashboard alerts is the check engine light. Often called the ‘engine malfunction light’ or simply the ‘engine warning light’, it indicates that your engine may not be operating correctly. Depending on the vehicle model, the symbol may appear yellow, amber, or orange.

If your check engine light comes on, it is recommended that a technician inspects your vehicle promptly to prevent more serious damage. If the light is flashing, this often signals a more urgent problem that should be checked immediately.

To diagnose the cause of a check engine light, an OBD2 scanner is required to read the fault codes stored within the vehicle’s system. At ESP Servicing, our Bosch OBD II diagnostic equipment reads these codes and provides detailed information about the issue. Our trained technicians can then recommend any repairs needed to resolve the problem and safely return your vehicle to the road. Once the issue is repaired, the warning light can usually be reset.

Not sure what a specific BMW fault code means? Has your Ford’s check engine light appeared unexpectedly? By connecting our OBD2 scanner to your vehicle’s ECU, we can read diagnostic codes from most major manufacturers including Vauxhall, Audi, Mercedes and Volkswagen.

Our experienced diagnostic technicians can interpret these codes and provide guidance on any repairs that may be necessary before the issue worsens.

On-board diagnostics are extremely useful for monitoring your vehicle’s health. A full diagnostic scan can typically provide information about:

• Engine management faults
• Transmission issues
• Ignition coil problems such as misfires or abnormal RPM levels
• Throttle performance
• Exhaust system condition
• Brake system health
• Engine coolant levels
• Fuel injection performance
• Ignition timing
• And many other systems.

Although diagnostics mainly focus on engine performance, depending on the vehicle, the scan may also gather information about additional systems including lighting, tyres, and comfort features.

The price of an on-board diagnostic test can vary depending on factors such as the service provider and the vehicle model. Some vehicles require specialised equipment, while high-performance or unique models may need dedicated diagnostic tools.

On average, a diagnostic scan typically costs between £50 and £100. Regular vehicle maintenance and occasional diagnostic checks can help detect problems early and reduce the risk of expensive repairs later.

You can arrange a diagnostic fault code scan at ESP Servicing. Our trained technicians will read and analyse the fault codes using professional OBD diagnostic tools and provide advice on any issues identified.