Plain English explanations · VAG specific notes · India, UK and US repair costs
Fault code explanations are written from real car ownership experience and OBD2 diagnostics. Repair costs shown are estimated ranges based on typical market rates in India, UK and US — actual costs vary depending on your location, vehicle model, and garage. Always get a quote before authorising any repair.
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What Is an OBD2 Fault Code?
An OBD2 fault code — also called a Diagnostic Trouble Code or DTC — is a standardised alphanumeric code your car’s ECU generates when it detects a problem. Introduced as part of the OBD2 standard mandated in all petrol and diesel cars sold in Europe from 2001 onwards, these codes are the first clue your car gives you when something isn’t right. When your check engine light or malfunction indicator lamp illuminates, there’s always at least one fault code stored in the ECU waiting to be read.
Can You Drive With a Fault Code?
Not all fault codes carry the same urgency. Some codes — like a minor EVAP emissions fault — are safe to monitor while you arrange a repair. Others, such as misfires (P0300–P0304), low oil pressure warnings, or transmission faults, require you to stop driving immediately to avoid serious engine damage. As a general rule, if the check engine light is flashing rather than steady, treat it as urgent. A permanent fault code means the fault is currently active, while a pending code means it has been detected but not yet confirmed across multiple drive cycles.