Fault code P1122 – a step-by-step guide to diagnosing and fixing it

Error code P1122 is displayed and the check engine light is on - what does this mean?

The DTC P1122 is a manufacturer-specific error code that is recognized by the OBD system and indicates a problem with the throttle position or the mass air flow sensor. This trouble code mainly occurs in Volkswagen, Audi, Seat and Skoda vehicles and indicates a fault in the intake system.

What causes can this error code have?

• Defective mass air flow sensor (MAF sensor)
• Dirty or defective throttle valve
• Leaking intake lines or hoses
• Faulty throttle valve control
• Damaged wiring to the mass air flow sensor
• Defective engine control unit
• Clogged air filter
• Loose or corroded plug connections

What symptoms occur in parallel with fault code P1122?

• Uneven idling: The engine runs unevenly at idle speed
• Loss of power: Noticeable reduction in engine power
• Increased fuel consumption: The vehicle consumes more fuel than usual
• Starting problems: Difficulty starting the engine, especially when the engine is cold
• Jerking when accelerating: The engine stutters or jerks under load
• Black smoke from the exhaust: Signs of incomplete combustion

How to fix the problem of fault code P1122?

• Repairing fault code P1122 requires a systematic diagnosis of the intake system.
• Clean or replace the mass air flow sensor, as this sensor often fails due to contamination and a complete replacement is often the best solution
• Remove the throttle valve, clean thoroughly with a special cleaner and then carry out a basic adjustment
• Check all intake hoses and connections for cracks or leaks and replace damaged parts
• Check the wiring to the mass air flow sensor for damage and repair or replace defective cables
• Replace the air filter if it is very dirty, as a clogged filter can falsify the measured values
• Check the engine control unit with a professional diagnostic device and reprogram or replace if necessary