DTC P011B: Engine Coolant Temperature / Intake Air Temperature Correlation [08/2015 - 08/2017]: Description

The engine has two temperature sensors, an engine coolant temperature sensor and an intake air temperature sensor, to detect temperature while the engine is in operation. A thermistor, whose resistance value varies according to temperature, is built into each sensor. When the temperature is low, the resistance of the thermistor increases. When the temperature is high, the resistance drops. These variations in resistance are transmitted to the ECM as voltage changes. Based on these temperature signals output from the sensors, the ECM determines the fuel injection time and ignition timing to control the engine.

DTC Code	DTC Detection Condition	Trouble Area
P011B	All conditions are met (2 trip detection logic): The battery voltage is 10.5 V or higher. 7 hours or more have elapsed from the engine stop of the previous trip. 25 seconds have elapsed after a cold engine start. The minimum intake air temperature after the engine starts is higher than -10°C (14°F). The average engine coolant temperature before the engine starts is higher than -10°C (14°F). The result of (engine coolant temperature - intake air temperature) is outside of the range of -25 to 25°C (-45 to 45°F).	Intake air temperature sensor Engine coolant temperature sensor ECM

Fig 1: Engine Coolant Temperature VS Intake Air Temperature Graph

HINT:

Waiting is required to prevent the temperature of the engine from affecting the readings. If the engine has been operated recently, it will not be possible to accurately compare the readings.
For diagnosis, in order to duplicate the detection conditions of the DTC, it is necessary to park and leave the vehicle for 7 hours. Leaving the vehicle for 7 hours ensures that the actual engine coolant temperature and intake air temperature are very similar. When the vehicle has been left for less than 7 hours, differences in the readings may exist. However, this does not necessarily indicate a fault.