4 Wire Wiring Diagram Temp Sensor. With the sensor unplugged the pcm should show 40 or so and with the pcm signal wire jumpered to ground the pcm should show max temp whatever that is in celsius. Damaged or loose wiring connections.
The temperature is a function of the air velocity as the faster the velocity the lower cooler the wire temperature. Ground sensor wiring shield at the sensor if possible. 3 wire sensor these rare coolant temperature sensors are a 1 wire sensor and a 2 wire sensor in one package.
3 wire pt100 rtd sensor wiring system.
Current source transmitter non isolated 3 wire current sink transmitter non isolated 3 wire fully isolated 4 wire two wire loop powered transmitters. Damaged or loose wiring connections. It sends the reading to the car computer ecu which adjusts the amount of fuel injection into the combustion chamber. Rtd lead wire configuration per iec 60751 single element.