Examination
1. The ECT sensor is a thermistor (resistor whose resistance changes with temperature). A change in sensor resistance has a direct effect on the amplitude of the signal output by the sensor to the ECM/PCM. At the same time, with a DECREASE in temperature, the resistance of the sensor INCREASES, and vice versa. If there is a corresponding DTC in the ECM/PCM memory (see On-Board Diagnostic System (OBD) - the principle of operation and fault codes) check the condition of the ECT circuit and, if the wiring is OK, replace the sensor.
2. Checking the sensor is done by measuring its resistance (see accompanying illustration) cold (10°С÷27°С). then start the engine and warm it up to normal operating temperature. The resistance of the sensor should drop.
3. Measure the supply voltage at the red-black wire terminal of the sensor wiring connector with the ignition on (do not start the engine). The measurement should read about 5.0 V, otherwise check the wire for an open from the sensor to the ECM/PCM.
Replacement
Attention! Wait until the engine has completely cooled down before proceeding with the procedure.
1. Before installing a new sensor, its threaded part should be wrapped with Teflon sealing tape (FUM tape).
2. Press out the locking tab, then carefully unscrew the sensor. To minimize coolant loss, screw in a new sensor as soon as possible.
Attention! Handle the ECT sensor as carefully as possible, as damage to it can have a noticeable effect on the functioning of the power system as a whole.
3. Installation is carried out in the reverse order. Finally, check the coolant level and correct if necessary (see chapter Current service).