What is a Fuel Level Sensor & How does it Work?

If you are a fleet manager, there is no denying that fuel management is the most difficult duty in monitoring the overall fuel cost. Fuel monitoring is regarded as an important aspect of fleet management; it will assist fleet managers in reducing the large bite of fuel usage in operations.

Your fleet depends on fuel because you need a monitoring system for tracking and evaluating fuel consumption and expense. Fuel management software is intended to measure and manage fuel consumption in various industries. This is where fuel level sensors step in.

A fuel level sensor such as LocoNav’s is a gadget that measures the amount of fuel in a vehicle’s tank precisely. These metrics, when paired with GPS monitoring and telematics platform functionality, yielded amazing results.

Manage your fleet efficiently with LocoNav’s Fleet Management Solutions!

What are the different components of the fuel level sensor?

Fuel sensors can be rather complex, from the typical components visible on the outside to the delicate components on the interior, to ensure a precise fuel reading. In this section, we’ll look at the components utilized in a fuel level sending unit, as well as their function, how they operate, and the components that make them up.

  1. Measurement Rod – This is dipped into the tank and calibrated for various levels of fuel.
  1. Telematics Unit – This part ensures that the fuel levels are correlated with the location of the vehicle.
  1. Bluetooth Module – A wireless BLE transmitter on the Fuel Sensor wirelessly transmits the fuel level from the tank to the Telematics Unit. 
  1. GSM Modem – Fuel level data received from the Bluetooth/ Wired Fuel Sensor is transmitted to the fleet manager via the internet using a GSM Modem along with the Telematics Data. 
  1. SIM Card – For internet connectivity of the sensor.
  1. Signal Cable – To ensure constant connection between the Fuel Sensor and the Telematics Unit. It is resistant to breaks and weather conditions.
  1. Calibration Tool – Used to calibrate the Fuel Sensor post-installation in the Vehicle.

How does a fuel tank level sensor work?

The working principle of a fuel level sensor is:

The fuel tank is emptied and cleaned and the geometric position is decided where the fuel sensor is to be installed based on the Tank Shape and Size.

The fuel sensor is cut as per the depth and size of the fuel tank. After cutting the sensor, calibration is done to detect empty and full values.

The fuel sensor is installed in the fuel tank and it is connected to a laptop using the OEM adapter. The fuel sensor is then configured as per the vehicle and laptop.

The vehicle is then taken to the refueling station and sensor reading is noted for empty and every 5L level until the tank is at its full capacity.

Types of Fuel Level Sensors Available in the Market

A fuel level sensor is used to monitor, maintain, and measure the level of fuel in a vehicle. After detecting the fuel level, the sensor turns the observed data into electronic signals.

Fuel level sensors are divided into three types: digital, analog, and Bluetooth.

  1. Digital Output Interface Sensor

Digital Sensor provides the output in a range of discrete values over RS232 or RS485 outputs. It keeps on changing as the fuel is consumed and the level of the fuel in the vehicle is changed. These are comparatively better in terms of accuracy, it is connected to the RS232 or RS485 inputs of the Telematics Unit to push the raw data to the server.

  1. Analog Output Interface Sensor

The sensor essentially provides the variating voltage output at the sensor terminals while the vehicle moves and starts consuming the fuel. While installing the fuel sensor, the output vis noted at the empty tank and at after every 5 – 10% of the level to all way to its full capacity. It’s then connected to the analog input port of the device to capture and send the raw output voltage of the analog sensor to the server.

  1. Bluetooth Output Interface Sensor

It is fully wireless, has no wires, and communicates over Bluetooth with the supported Telematics Unit. An important factor to note here is the distance and obstruction between the Sensor and Telematics Unit should be carefully measured during the installation since it could lead to data drops.

What are the benefits of using a fuel level sensor?

While there are numerous benefits to employing technology in your fleet, here are the top 4 advantages of using a fuel level sensor:

  • Drivers can now easily modify their fuel expenses. So, if you want to know how much fuel was replenished when it was refilled, and where it was refilled. If you install LocoNav’s fuel level sensor; 
  1. It will decrease fuel waste and abuse.
  2. You can receive fueling and drain warnings by SMS or email.
  3. The map shows the locations of refueling and draining stations.
  4. Reports on refueling and draining are complete.
  5. Alarms can be pre-programmed to notify you of high or low fuel levels.
  • It is a boon for fleet managers to recognize which machine is not running properly/requires maintenance/should be discarded/or declared trash with the use of various types of information given by a Fuel Monitoring System.
  • A Fuel Monitoring System creates reports that compute the miles traveled by the fleet and the amount of fuel spent by them, allowing the user to easily calculate the Cost per Mile, reach the mileage of the fleet, and determine performance levels.
  • Fuel reconciliation reports can be generated at the press of a button in the fuel monitoring reports to determine fuel losses and short fills, which is nearly impossible to achieve in a manual tracking environment.


How to know if your fuel level sensor is not working properly?

  • The gasoline gauge should never fluctuate or behave abnormally. 
  • It is also common for the fuel tank to show as empty when it is not. If you put fuel in the tank but the gauge does not move, it is a strong indication that the transmitting unit has failed.
  • While it is less typical, when the sender fails, the gauge can indicate full. A fuel gauge that is stuck at maximum is usually the result of a faulty resistor.

Can you drive without a fuel level sensor?

Yes. As long as a malfunctioned fuel level sensor does not interfere with the normal operation of the vehicle, you can drive without it.

How reliable is a fuel sensor?

The average inaccuracy in the fuel efficiency display of vehicles is 2.3 percent. However, vehicle error varies substantially, ranging from 6.4 to 2.8 percent. This specific data indicates that each car reacts differently to changes in driving, and that accuracy can be influenced by driving style and road conditions.

What are the disadvantages of a fuel level sensor?

  • Low outdoor temperatures, as well as poor gasoline quality, can impair the sensors’ ability to determine the fuel level appropriately.
  • The percentage of measurement inaccuracy increases with travel times traveled.
  • Because they are electrical devices, they can be manipulated to change their behavior.
Back to Top