WH commodore coolant temp sensor

[larz martin-walsh]

hey guys, i have a WH statesmen 5.7lt in my shop has common code for coolant temp sensor, "low circuit input" but has changed to "high voltage" after clearing code, it has 2.5-2.8 volts to the sensor ha brand new sensor in vehicle. my thought was it is meant to have 5v to plug. is this the ecu/pcm not sending enough voltage?

 

[BlackVXGTS]

What are the actual DTC numbers? We can then provide you with further advice:

ENGINE COOLANT TEMPERATURE (ECT) SENSOR
The Engine Coolant Temperature (ECT) sensor is a thermistor (a resistor which changes value based on temperature) mounted in the left cylinder head. Low coolant temperature produces a high resistance (100,000 ohms at -38°C) while high temperature causes low resistance (70 ohms at
130°C).

The PCM supplies a 5.0 volt signal to the engine coolant temperature sensor through a resistor in the PCM and measures the voltage. The voltage
will be high when the engine is cold. The voltage will be low when the engine is hot. The PCM calculates the engine coolant temperature by
measuring the voltage. The engine coolant temperature affects most systems the PCM controls.

The Tech 2 scan tool displays engine coolant temperature in degrees. When the engine starts the engine coolant temperature should rise steadily
to about 90°C then stabilise when thermostat opens. The engine coolant temperature and intake air temperature should be close to each other if the
engine has not been run for several hours (overnight). The following DTCs set when the PCM detects a malfunction in the engine coolant temperature sensor circuit:

• DTC P0117: ECT Sensor Circuit Low Voltage.
• DTC P0118: ECT Sensor Circuit High Voltage.
• DTC P0125: ECT Excessive Time to Closed Loop Fuel Control.
• DTC P1114: ECT Sensor CKT Intermittent Low Voltage.
• DTC P1115: ECT Sensor CKT Intermittent High Voltage.