Operation CHARM: Car repair manuals for everyone.

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 B1202 if there is an open circuit in water temp sensor signal harness or the measured resistance value of the sensor is more than the threshold value (about 176.3 Kohms)

DTC Detecting Condition





Schematic Diagram





Signal Waveform

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