Engine Coolant Temperature Sensor

GENERAL INFORMATION

The signal from this sensor is used by the control unit to control the fuel and ignition systems, and to switch on the cooling fan.

The sensor is screwed into the intake manifold.

The sensor is a thermistor.

A regulated voltage is supplied to the sensor, and the output signal is determined by the change in sensor current as temperature changes.

If the sensor fails (the warning lamp on the instrument panel illuminates), control passes to a backup circuit that uses default base values.

Inspection

PROCEDURE

1. To check the sensor, remove it and measure its resistance at different temperatures.

2. Do not check the sensor while it is installed in the vehicle.

3. A complete check of the sensor circuit and the engine control system must be carried out at an authorized service center.

Removal

PROCEDURE

1. Disconnect the battery ground cable.

2. On a cold engine, drain some of the coolant to the level of the thermoswitch.

3. Disconnect the thermoswitch connector.

4. Carefully unscrew the thermoswitch and remove the seal (if equipped).

Installation

PROCEDURE

1. Clean the thermoswitch and apply sealant to the threads.

2. Replace the seal (if equipped).

3. Install in the reverse order.