9-5 (9600) L4-2.3L Turbo (B235) HO (2003)
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Fuel Gauge: Description and Operation
Fuel Gauge
The fuel gauge gives the driver information on how much fuel is left in the tank.It consists of a fuel gauge in the main instrument unit and a level sensor
in the tank.
The level sensor has variable resistance where the value corresponds to the level of the float sensor in the tank, and the resistance increases with a higher
fuel level.
The sensor is connected to the main instrument unit control module, pin 4, when supplied with B+ and grounded in pin 10.
The control module knows the resistance value of the sensor and sends the voltage pulses to the fuel gauge so that the needle position corresponds to the
resistance value of the sensor.
To enable a more accurate display with small amounts of fuel in the tank, the main instrument display control module switches to measuring fuel
consumption once the amount of fuel drops below 10 litres.
The main instrument unit control module sends information on the fuel level to the buses.
Fuel reserve indicator lamp
With about 10 litres of fuel remaining in the tank, the lamp lights up to indicate low fuel level. The lamp is supplied with current from the main
instrument unit and grounded by the main instrument unit's control module when it is turned on.
The main instrument unit lights this lamp for three seconds when the ignition is switched on.
Fuel consumption
The engine control module sends information on the fuel quantity consumed to the bus.
The main instrument unit control module uses the information to control the fuel gauge (under 10 litres).
Diagnostics
An open circuit/short circuit sets diagnostic trouble code B1720. The gauge needle indicates 0 litres and the fuel reserve indicator lamp lights up.
