Fault code P0111 – a step-by-step guide to diagnosing and fixing it

Error code P0111 is displayed and the check engine light is on - what does this mean?

The OBD system detects an error in the intake air temperature sensor (IAT sensor) that is outside the expected range. This DTC P0111 indicates a problem with the sensor or its circuit, which means that the engine control unit is not receiving correct data about the intake air temperature.

What can cause this error code?

• Defective intake air temperature sensor (IAT sensor)
• Damaged or corroded cable connections to the sensor
• Loose or dirty plug connections
• Short circuit or interruption in the sensor wiring
• Defective engine control unit (rare)
• Dirty or clogged air filter
• Leaks in the intake system

What symptoms occur in parallel with fault code P0111?

• Starting problems: The vehicle is difficult to start, especially in cold temperatures
• Uneven idling: The engine runs unevenly at idle speed
• Increased fuel consumption: The engine control unit cannot optimally adjust the air/fuel mixture
• Loss of power: Reduced engine power while driving
• Black smoke: Incomplete combustion due to incorrect mixture ratio
• Check engine light: The warning light lights up permanently or flashes

How can the problem of error code P0111 be rectified?

• The repair requires a systematic diagnosis of the intake air temperature sensor and its components.
• Sensor replacement: Replace the defective IAT sensor with a new original part or equivalent spare part and then test the system
• Cable repair: Check and repair damaged cables between sensor and control unit, insulate exposed areas and replace corroded connections
• Clean plug connection: Remove corrosion and dirt from the plug contacts with contact spray and ensure a firm connection
• Change the air filter: Replace a dirty air filter and check the entire intake system for leaks
• Clear fault code: After the repair, clear the trouble code with an OBD scanner and perform a test drive to confirm the repair