General Information

Component Location





General Description

A water temp sensor located at heater unit detects coolant temperature. Its signal is used for cold engine lockout control. When the driver operates the heater before the engine is warmed up, the signal from sensor causes the heater control unit to reduce blower motor speed until coolant temperature reaches the threshold value.

DTC Description

The ECM sets DTC B1203 if there is a short circuit in water temp sensor signal harness or the measured resistance value of the sensor is less than the threshold value (about 1.2 Kohms)

DTC Detecting Condition





Schematic Diagram





Signal Waveform

** Resistance value of water temp sensor as a function of temperature.