General Information

Air Conditioner
B1203 Heater Water Temperature Sensor Short(Low) - General Information

Component Location





General Description

A water temp sensor located at heater unit detects coolant temperature. It contains negative type themistor whoses resistance value is in inverse proportion to temperature. Resistance of watersensor that varies with temperature makes signal voltage of A/C ECU change. In this way A/C ECU detects temperature. Signal of water sensor is used for cold engine lockout control - When the driver operates the heater before the engine is warmed up enough, to prevent driver from unpleasantness of cold air. the heater control unit reduces blower motor speed until coolant temperature reaches the threshold value.

DTC Description

Air conditioner Control Module sets DTC B1203 if Water sensor has been detected below 0.1V for 4 seconds.

DTC Detecting Condition





Specification

** Resistance value of Water temperature sensoras a function of temperature.






Diagnostic Circuit Diagram