504045238 TANK DETECT.

IVECO FUEL LEVEL SENSOR

🔧 What is the fuel level sensor?

It is a level sensor installed inside the diesel tank, whose function is:

• Measure the fuel level.

• Send that information to the instrument panel to display it on the needle or digital screen.

• In some cases, assist the ECU in calculating range, average consumption, or alerting to a low level.

⚙️ How does it work?

✅ Main components of the fuel level sensor:

1. Floating arm with a float (buoy).

2. Variable resistor (rheostat).

3. In some models: integrated feed pump.

4. In other cases: built-in diesel filter or pre-filter.

🔁 Operation:

1. The float rises or falls depending on the fuel level.

2. It is connected to a moving arm connected to a variable resistor.

3. The higher the level → lower resistance → different electrical signal to the ECU or panel.

4. The lower the level → higher resistance → the system translates it as “low tank”.

5. The system can operate with signals:

   • Analog (variable resistance).

   • Digital (CAN BUS) in newer models.

📍 Where is it located?

• Inside the fuel tank, normally accessible from above.

• In some models, the fuel level sensor can be removed from a top cover under the cab or in the chassis.

📈 Typical electrical values (in resistive systems)

These values may vary depending on the model and manufacturer.

🚨 Symptoms of fuel level sensor failure

• The needle or digital indicator does not show or remains fixed.

• Shows incorrectly (e.g. full tank but needle on reserve).

• Low fuel warning light on even though the tank is full.

• Communication failures with the ECU (in models with CAN BUS).

• In models with an integrated pump: starting or diesel supply problems.

🛠️ Diagnosis and testing

1. Multimeter:

   • Disconnect the fuel level sensor connector.

   • Measure the resistance between the terminals of the rheostat while manually moving the float.

   • It should vary smoothly and progressively.

   • If the reading is erratic or does not change → damaged fuel level sensor.

2. Diagnosis (IVECO E.A.SY, Jaltest, TEXA):

   • Digital reading of the fuel level.

   • Checking for errors such as:

🧠 Useful tips

• If the truck has two tanks, there may be two synchronized fuel level sensors, or a single one that calculates the average.

• The fuel level sensor does not measure exact liters, but the float position, which is interpreted by the ECU according to the shape of the tank.

• Do not use generic fuel level sensors without checking compatible ohms.

• On sloped terrain or during hard braking, the reading may momentarily vary.

Example:

Model > 100E18 EUROCARGO MY 2008

Plate > 50-72-20