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How to check the coolant temperature sensor


How to check the coolant temperature sensor</a>

Quite often motorists are faced with the problem of car overheating. This is mainly due to a malfunction of the coolant temperature sensor or due to the controller.

This article describes possible problems and their rational solution.



The controller's task is to calculate the temperatureCooling liquid. It is produced by the voltage drop across the sensor. From how well the coolant temperature sensor reads, most of the processes that are controlled by the controller directly depend.


Quite often there are problems due toDamage to the wires that approach the sensor. There are times when a wire break occurs near the sensor connector itself. Such problems cause the fan to turn on at low temperature. From the exhaust pipe there is black smoke. If such a malfunction occurs, the CHECK ENGINE warning lamp may not light up on the instrument panel. The engine in this case it is better not to jam, since then it may not start. It is still possible to move at low speed.


Problems can arise if it does not workCoolant temperature sensor. To test this sensor, you need to perform simple actions. First, detach the harness from the sensor. Turn the ignition on. We are engaged in testing the circuit. When measuring the voltage, on the contact "B" with respect to the "mass" should be about 5 V. If the voltage is less than 4.7 V, then the connection must be considered unreliable. It is possible that the wire closes to the "mass" or is torn. Also it is necessary to check up serviceability of the controller in this case.


Turn the ignition off and measure the resistanceBetween the contact of the sensor "A" and the "ground". The resistance must be at least 1 ohm and not more. If the resistance is greater than 1 ohm, then a wire break is possible.


Then you need to disconnect the controllerAnd check the resistance, which will be between the contact of the sensor "B" and the contact of the controller pad "45". It must be less than 1 ohm. If it is larger, then the connection in the pads is unreliable.


Next, measure the resistance between the "mass" and the contact "B" sensor pads. It must be at least 1 ohm. If less, then there is a short to ground.


We are engaged in testing the sensor. We measure the resistance at two temperatures of the cooling liquid. You need to do this on a cold and hot engine. Resistance should not be different. If there are differences, then it is necessary to replace the sensor. If the sensor and the circuit are in good condition, then we replace the controller.

How to check the coolant temperature sensor Was last modified: June 21st, 2017 By Kysbaihw
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