Volvo All Engines (2017 Emissions) Fault Code: P111E00 PID: EMS Engine Coolant Temperature Moderately High

The Engine Coolant Temperature Sensor is a thermistor. The resistance of the Engine Coolant Temperature Sensor changes inversely to the temperature of the engine coolant. When the coolant is cold, the sensor resistance is high. As the temperature of the coolant increases, the sensor resistance decreases.
The Engine Control Module (ECM) monitors the voltage drop across the Engine Coolant Temperature Sensor.
The coolant temperature signal is used to calculate fuel injection and to evaluate operating conditions of the engine coolant temperature. Examples of conditions that may cause high coolant temperature are: thermostat failure, fan failure, heavy load, high ambient temperatures and radiator blockage.
The sensor’s signal is monitored by the Engine Control Module (ECM).
The engine control module (ECM) will set a diagnostic trouble code (DTC) and derate the engine to avoid engine damage if the sensor signal is not within predetermined limits, or the signal is not rational.

Conditions for diagnostic trouble code (DTC):
1) Temperature too high

Observable symptoms
1) Engine de-rated

Probable cause
1) Engine cooling fan
2) Fan belt
3) Thermostat
4) Low coolant level
5) Clogged radiator
6) Clogged cooling system
7) Coolant pump drive belt
8) Coolant pump belt tensioner
9) Slipping impeller
10) Poor flow-through in the cooling system
11) Pressure cap, expansion tank
12) Engine coolant temperature sensor
13) Engine control module (ECM)