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OBD-II fault codes explained

A diagnostic code tells you what the vehicle detected. It is evidence for diagnosis — not proof that the component named in a code has failed.

Have a code from your scanner?

Add the code to an AutoAid guided diagnosis so it can be considered alongside your vehicle details and symptoms instead of being interpreted on its own.

Diagnose with my OBD code

Popular fault-code guides

Start with these high-interest generic OBD-II codes covering misfires, fuelling, emissions, turbocharging, DPF and timing faults.

Generic versus manufacturer-specific codes

Generic OBD-II codes apply across manufacturers, while many manufacturer-specific codes require the vehicle maker's service information for the exact definition and test procedure. AutoAid's live code lookup uses an open generic-code reference database and keeps code evidence separate from a final diagnosis.

AutoAid provides AI-assisted guidance only and never a guarantee. All faults, urgency ratings and prices are estimates — a physical inspection by a qualified mechanic may still be required.