Frost sensor (page 2 of 3)

Using suitable control logics for the sensors and adjustment with "self-learning" for the actuators, the electronic control unit is capable of recording and storing and series of problems and faults which can occur in the system.

When confronted with these problems, the control unit continues to manage the operation of the system replacing any incorrect values detected with appropriate recovery values which ensure a minimum level of operation for the system even if it is not ideal.

Two types of errors are memorized:

• occasional errors, which are zeroed when the key is turned OFF
• permanent errors: if an error occurs more than 5 times in a certain period it is considered permanent and is stored in the control unit memory; these errors are NOT zeroed when the key is turned OFF, but only after a specific external command (diagnostic equipment).

The control unit has two methods for reading errors it is storing:

• by means of the diagnostic equipment
• through the display in the on board panel enabled by reading the outside temperature.

As an error detected by the control unit occurs (even an occasional type error), the words "Error Cli" appear on the on board panel display to indicate that the system has memorized a fault.

By pressing the "outside temperature" button in the centre of the dashboard if these words remain, this means that the error involves the outside temperature sensor, if, on the other hand the correct temperature value appears, this means that the error relates to other system components and it is then possible to identify the fault memorized through the following procedure;

• Turn the left knob completely in a clockwise direction (HI position)
• Turn the right knob completely in a clockwise direction (MAX DEF position)
• Turn the centre knob (to position 0)
• Turn the ignition key from the OFF position to the ON position
• Within 10 seconds, turn the centre knob, placing it in the following positions: "0" - "AUTO" - "0" - "AUTO" - "0"