What is SPN 157 & How to Solve It?

What is SPN 157

SPN 157: Refers to a fault related to the Engine Control Module (ECM) and indicates an issue with the engine coolant temperature.

When SPN 157 is triggered, it indicates that the engine coolant temperature has exceeded or fallen below normal operating range, which could cause engine overheating or performance issues.

Why It Happened

This fault code is commonly caused by:

• Low coolant levels or coolant leakage.
  
• A malfunctioning thermostat.
  
• A faulty engine coolant temperature sensor.
  
• Damaged wiring or loose connections in the sensor circuit.
  
• A problem in the ECM processing the sensor’s data.
  
  

How to Resolve It

To resolve SPN 157:

1. Inspect coolant levels and refill if necessary.
   
2. Check the engine coolant temperature sensor and its wiring for damage or corrosion.
   
3. Replace the thermostat if it’s faulty.
   
4. Test and replace the coolant temperature sensor if needed.
   
5. Clear the fault code and restart the system to ensure the issue is resolved.
   
   

How to Avoid Before It Happens

To prevent SPN 157:

• Regularly inspect the cooling system, including the sensor and thermostat.
  Check coolant levels and top off when needed.
• Use Clue to monitor engine temperature data in real-time for early alerts on temperature issues.