What is MID 109 & How to Solve It?

What is MID 109:

MID 109 refers to a fault with the Intake Air Temperature (IAT) Sensor. The ECM has detected an out-of-range signal from the sensor, which can lead to incorrect air/fuel mixture management and reduce engine performance.

‍

Why This Happens:

• Faulty intake air temperature sensor.
  
• Shorted or damaged wiring in the sensor circuit.
  
• Loose or corroded sensor connectors.
  
• ECM failure to process the sensor’s data correctly.
  
• Incorrect air intake system readings affecting the sensor.
  
  

How to Fix It:

1. Inspect the intake air temperature sensor for visible damage or malfunction.
   
2. Test the sensor’s voltage and resistance to ensure it is functioning properly.
   
3. Check wiring and connectors for visible damage or corrosion.
   
4. Replace the faulty sensor if necessary.
   
5. Ensure the air intake system is functioning correctly.
   
   

How to Avoid It Before It Happens:

• Regularly inspect the intake air temperature sensor and its wiring.
  
• Perform routine air intake system maintenance.
  
• Keep connectors clean and corrosion-free.
  
• Perform diagnostic checks to monitor sensor health.
  
• Clue’s Equipment Maintenance services track air intake systems and sensors to prevent performance issues before they arise.