Table of contents: Disruptions in work ↓ Checking the coolant temperature… ↓
The coolant temperature sensor (1) in a four-cylinder engine is located at the rear of the cylinder head. You will find the sensor contact designation on the connector. 2 – plug of the second temperature sensor (air conditioning system).
In a six-cylinder engine, the coolant temperature sensor (2) is screwed into the coolant pipe behind the right cylinder head. The sensor connector (1) is removed here.
The coolant level indicator sensor (2) is installed at the bottom of the coolant expansion tank (1).
The coolant temperature indicator functions in the same way as the fuel tank indicator. The device receives current from the positive terminal when the ignition is on, and the connection to ground is provided by the engine temperature sensor. This sensor is a variable resistance that passes more current as it heats up, so more current is supplied to the instrument and the pointer moves further. Two different temperature sensors are combined in one housing. First, the injection system coolant temperature sensor (contacts 1 and 3) and secondly, the sensor that was mentioned here (contacts 2 and 4).
Tip: When the coolant temperature is too high, a flashing red warning light is also switched on. The operation of this light is controlled by the microprocessor in the combined instrument panel. The light also flashes when the coolant level drops. In vehicles with an automatic control system, a red symbol appears instead of the light "Kuhlmittel" – "Cooling liquid".
Disruptions in work
Incorrect readings of the coolant temperature indicator (most often with simultaneously inaccurate fuel quantity readings) allow us to conclude that the microprocessor in the combination instrument is faulty.
The absence of indication may be due to a faulty temperature sensor or device.
If the indication is correct and the alarm signal is flashing at the same time, the cause of the malfunction may also be in the coolant level indicator sensor in the expansion tank.
Checking the coolant temperature indicator
1. Disconnect the multi-pin connector on the engine compartment temperature sensor.
2. Single contact to temperature sensor (blue/brown wire) on contact 2 of the multi-pin connector, extend it with a piece of wire and apply it to the bare metal (ground). The contact designations are on the connector.
3. Turn on the ignition briefly.
4. If the previously stationary indicator arrow slowly moves along the scale and the control light flashes, then the temperature sensor is faulty – replace it.
5. If the indicator arrow remains stationary, then the defect is in the supply wire, in the microprocessor or in the indicator device itself. Its dismantling is described at the beginning of the chapter.
The text is based on materials from the website: audimanual.ru