What is CID 644 & How to Solve It?

What is CID 644:

CID 644 refers to a problem with the vehicle's engine management system, specifically related to the engine coolant temperature sensor. The ECM detects an abnormal reading, which can cause the engine to overheat or result in poor performance.

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Why This Happens:

• Faulty engine coolant temperature sensor.
  
• Shorted or damaged wiring in the sensor circuit.
  
• Low coolant levels affecting sensor readings.
  
• ECM misinterpretation of sensor data.
  
• Faulty engine control module (ECM).
  
  

How to Fix It:

1. Inspect the coolant temperature sensor for damage or malfunction.
   
2. Test the sensor’s voltage and resistance to ensure it operates correctly.
   
3. Check wiring and connectors for visible damage or corrosion.
   
4. Replace the faulty sensor if necessary.
   
5. Ensure proper coolant levels and circulation.

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How to Avoid It Before It Happens:

• Regularly inspect the coolant temperature sensor and wiring.
  
• Perform routine engine coolant maintenance.
  
• Keep connectors clean and free from corrosion.
  
• Maintain proper coolant levels to prevent sensor failure.
  
• Clue’s equipment maintenance services monitor engine cooling systems and prevent overheating or performance issues.