Audi Q5 Fault Codes | List

That’s the “your expensive catalytic converter is dying” code. On a Q5, often from ignored misfires or a leaking fuel injector. Cost? A few thousand. I learned: never ignore P0300 when it’s small, or it grows into P0420.

Failed catalytic converter, O2 sensors, or dirty throttle body. DPF Soot Buildup Diesel Intake audi q5 fault codes list