Decode your dashboard.

OBD stands for On-Board Diagnostics. Your car's computer constantly monitors hundreds of sensors. When something goes wrong, it stores a code (like P0300) in memory and usually triggers a warning light. A code reader plugged into your car's OBD port retrieves these codes.

Whether a vehicle is safe to drive depends entirely on the underlying cause, which only an in-person diagnosis can confirm. Codes are typically grouped into severity tiers. Many minor B-codes and P4xx emissions codes are commonly considered lower urgency. Moderate codes generally warrant prompt diagnosis. Critical codes (such as oil pressure, coolant, or chassis C0xxx codes) are typically considered urgent. Always confirm with a qualified mechanic before deciding whether to continue driving.

Clearing a code removes the warning light but does not fix the underlying fault. The code will typically return once the car's systems re-test, usually within a few drive cycles. Generally, addressing the underlying cause first is more reliable than clearing the code in isolation.

Some very new codes, proprietary manufacturer codes, or codes from specialist equipment may not be in our library. If you can't find your code, try searching by keyword or check with a garage who can run a full manufacturer-level diagnostic.

You can't without some form of diagnostic tool. Basic OBD-II readers start from around £15 online and plug into the diagnostic port usually found under the dashboard on the driver's side. Many garages and fast-fit centres will read codes for free.

Cost Savvy Motors Limited, a UK company with over twenty years in the automotive industry.