P0115: Engine Coolant Temperature Circuit Malfunction

What does P0115 mean?

P0115 is a diagnostic trouble code indicating "Engine Coolant Temperature Circuit Malfunction". A component in the cooling system has been flagged as malfunctioning by the vehicle's ECU. This requires diagnosis to determine whether the part itself has failed or if there is a related wiring or control issue.

Symptoms you may notice

• Check engine light (MIL) illuminated on dashboard
• Engine overheating
• Temperature gauge reading high
• Heater not working properly
• Intermittent warning lights

Common causes

• Stuck thermostat (open or closed)
• Low coolant level or coolant leak
• Failed coolant temperature sensor
• Faulty water pump
• Blocked radiator

What should you do?

This is a significant issue that should be diagnosed and repaired soon. Avoid long trips or heavy driving until the problem is resolved. Continued driving may cause additional damage.