DTC P011B: Engine Coolant Temperature / Intake Air Temperature Correlation: Description

WARNING: This page is about a different variant/trim than selected.

The engine has two temperature sensors, an engine coolant temperature sensor and an intake air temperature sensor, to detect the temperature while the engine is operating. A thermistor, whose resistance value varies according to the temperature, is built into each sensor. When the temperature is low, the resistance of the thermistor is high. When the temperature is high, the resistance is low. 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 duration and the ignition timing to control the engine.

DTC No.	DTC Detection Condition	Trouble Area
P011B	All of following conditions are met: (2 trip detection logic) Battery voltage 10.5 V or more 7 hours or more elapsed from engine stops on previous trip 35.2 seconds or more after cold engine starts Either of following conditions is met The minimum intake air temperature after the engine starts -10°C (14°F) or more Engine coolant temperature before engine starts -10°C (14°F) or more Difference between readings of engine coolant temperature and intake air temperature greater than 20°C (36°F)	Intake air temperature sensor (built into mass air flow meter) Engine coolant temperature sensor ECM

Fig 1: View Of Intake Air And Coolant Temperature Graph

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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 the vehicle for 7 hours. Parking the vehicle for 7 hours ensures that the actual temperature of the engine coolant temperature sensor and intake air temperature sensor are very similar. When the vehicle has been parked for less than 7 hours, differences in the readings may exist, this does not necessarily indicate a fault.