P0135 (Audi): Defective Oxygen Sensor/Air Fuel Ratio Sensor, defective Oxygen Se… — what it means, the affected system and what to check before replacing parts.
Defective Oxygen Sensor/Air Fuel Ratio Sensor, defective Oxygen Sensor/Air Fuel Ratio Sensor Heater Circuit, Exhaust System Leak, Intake Air System leak, Low Fuel Pressure, Defective Engine Coolant Temperature Sensor, Defective sensor wiring and or circuit problem, PCM software needs to be updated, Defective PCM. Source catalogue definition; confirm applicability using vehicle service information.
Affected system: Powertrain