Injection - PIAGGIO 500 cc Service Manual

The coolant temperature sensor mounted on the engine head, supplies indications to the digital instrument and fuel

injection.

It is constructed with two electrically distinct sections.
The fuel injection section has a NTC sensor connected with a 5V feed circuit. The resistance variation causes a circuit
tension variation. This tension is linked to a temperature value.
With this information, the control unit can manage the engine functioning, optimizing it for all temperatures.
Damage to this circuit causes the fuel injection indicator to light up and protective action (amongst which continuous
running of the electrical fan). Under these conditions, the engine can still function even if not at optimum standard,
but always safeguarding the integrity of the catalyctic converter.
The most difficult anomaly to manage is an unreal temperature indication, but one which is comprised in the possible
temperatures field. This may lead to a lack of protective action and incorrect carburation management. Such an
anomaly can be highlighted more easily at ignition stage.
To check the sensor and related circuit proceed as follows.
Check if anomalies concerning the coolant temperature sensor have been registered.
NO
The EMS system has not received temperature indications that are not included in the field of
If it is suspected that a temperature indication is incorrect, proceed in any
NOTE: an incorrect temperature indication may be perceived by matching it with the analog
instrument indication on activation of the electrical fan.
In all cases, before proceeding with the sensor control, check the filling and drainage of the
cooling system. See Chapter. 1 - GENERAL INFORMATION AND MAINTENANCE.
Before proceeding with control of the sensor and related circuit, it is advisable to wait until the engine has
cooled completely so that the vehicle is adjusted to the working environment temperature.
Set ignition to "ON" with switch on "RUN" and side stand raised.
The three indications are equal or differ by little (for example 1°C).
YES
The temperature sensor is probably giving a correct indication.
Install the special tool 020481Y. See page 9-8. Do not connect the control unit connector.
Connect the diagnosis tester 020460Y. See page 9-17.
Select the "errors" function from the menu.
possible temperature.
event as indicated below.
Select the "parameters" menu.
Do not start the engine.
Check indications for:
coolant temperature
air intake temperature
ambient temperature indicated by the digital instrument
Proceed with control at ~80° C
Fuel injection
YES
9
NO
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