Table of contents: Petrol models without air…🠇 Petrol models with air conditioning…🠇 Fuel injection control system…🠇
Petrol models without air conditioning
Examination
1. Power is supplied to the cooling fan via the ignition switch and fuse. On petrol engines without air conditioning, the fan is controlled by a temperature sensor installed in the radiator on the left side. On petrol engines with air conditioning and all diesel engines, the fans are controlled by a "Bitron" sensor.
2. The fan should turn on when the engine operating temperature is exceeded, i.e. a few minutes before the engine temperature gauge needle enters the red sector or before the coolant temperature warning lamp lights up. If the fan does not turn on, remove the wires from the temperature sensor, connect them together and turn on the ignition. If the fan starts working after this, the temperature sensor is probably out of order and needs to be replaced.
Removal
1. The temperature sensor is installed in the radiator on the left side. Before removing the temperature sensor, the engine and radiator must be cold.
2. Disconnect the negative battery terminal.
3. Partially drain the coolant from the cooling system so that the coolant level is below the sensor. Alternatively, you can not drain the coolant from the cooling system, and after unscrewing the sensor, very quickly install a plug in place of the sensor. In this case, you must be careful not to damage the radiator.
4. Remove the wires from the sensor contacts.
5. Carefully unscrew the sensor from the radiator.
Installation
1. Replace the O-ring before installing the sensor.
2. The sensor is installed in the reverse order of removal. Securely tighten the sensor and refill the cooling system.
3. Start the engine and warm it up to operating temperature. If the temperature continues to rise, check the fan activation with the sensor.
Petrol models with air conditioning and all diesel models
The cooling fans are controlled by a "Bitron" sensor, which is located in the thermostat housing on the left side of the cylinder head.
Examination
The "Bitron" sensor also controls the air conditioning system and its functionality must be checked at a specialized Peugeot station.
Removal and installation
1. The Bitron temperature sensor is screwed into the thermostat housing on petrol engines or the fuel filter housing on diesel engines, which is bolted to the left side of the cylinder head. The sensor can be identified by the brown colour of the wire going to the sensor.
2. Removal and installation are similar to those previously described for the radiator fan thermal switch.
Fuel injection control system coolant temperature sensor
Examination
1. The coolant temperature sensor in the fuel injection control system is screwed into the thermostat housing, which is bolted to the left side of the cylinder head. The sensor can be identified by the green wire that goes to the sensor.
2. The sensor is a thermistor. The electronic control unit (ECU) supplies voltage to the sensor and, by measuring the current flowing through it, determines the engine temperature. This information is used by the ECU to control the injector opening time (pulse width). On some models, idle speed and ignition timing are also determined by engine temperature.
3. If the sensor fails, the ECU system enters the backup mode, i.e. it accepts a preset value that will allow the fuel injection system to operate, although with less efficiency. In this case, the corresponding warning light will light up on the instrument cluster, which means that you should contact a service station as soon as possible. This sensor can be checked using special Peugeot diagnostic equipment. Do not try to check the sensor using equipment not intended for this purpose, as you can damage the ECU.
Removal and installation
The Bitron temperature sensor is screwed into the thermostat housing on petrol engines or the fuel filter housing on diesel engines, which is bolted to the left side of the cylinder head. The sensor can be identified by the brown colour of the wire going to the sensor.