How to Fix Fuel Level Jumps in CAN or OBD Data in Teltonika FMB Devices
Introduction
When monitoring fuel level via CAN or OBD interfaces on Teltonika FMB devices (e.g., FMC003, FMB150), you may notice the reported fuel level on your server fluctuates rapidly or “jumps”, even when the vehicle is not consuming fuel or is stationary. This leads to unreliable fuel consumption data and false alerts.
Cause
Fuel level jumps are usually caused by:
- Sensor fluctuations in the fuel tank during vehicle movement.
- Noise or unstable readings in the CAN/OBD data stream.
- High sensitivity of immediate raw data without smoothing.
Solution: Use the Averaging Constant (Averaging Const)
Teltonika devices provide an Averaging Constant parameter that smooths incoming fuel level data by applying exponential moving averaging. This helps reduce sudden jumps and stabilizes the data reported to your server.
What Does Averaging Const Do?
The Averaging Constant controls how quickly the device’s reported fuel level adapts to changes. A higher value means slower updates but smoother, less jumpy data. A lower value means faster updates but more fluctuations.
If Avg Const value is 10, new value must be present for 1 second to register the change to a new value.
NOTE: Average Constant is not used as an activation timer or delay timer. But it is used as a filter.
How to Configure Averaging Const
- Open Teltonika Configurator and connect your device.
- Navigate to the fuel level IO element under IO settings.
- Locate the Averaging Const parameter
- Set a value depending on your smoothing preference:
- 2500 to 5000 Moderate smoothing (recommended starting point).
- 6000 or higher Strong smoothing for very unstable signals.
- Save and upload the configuration to the device.
- Monitor the server data for improved fuel level stability.
Tips
- Adjust the value gradually—setting it too high could delay the response to real changes in fuel consumption.
- Always keep your device firmware updated for best CAN/OBD data handling.