The DEF (Diesel Exhaust Fluid) head unit is a vital component in diesel vehicles that use a Selective Catalytic Reduction (SCR) system. Its main role is to manage and monitor the DEF tank, ensuring accurate data is sent to the vehicle’s computer for emissions control.
The DEF Head Unit Performs Several Key Functions:
- Measures DEF Fluid Level
- It tracks how much DEF is in the tank and communicates that to the vehicle’s dashboard and ECM (Engine Control Module).
- Monitors Temperature
- It detects the fluid’s temperature, helping to prevent freezing or overheating that can affect system function.
- Controls Tank Heater
- In cold weather, the unit activates a heater to thaw the DEF so it can flow through the system properly.
- Sends Data to the ECM
- The head unit shares real-time information with the engine’s control system to help regulate DEF dosing in the exhaust stream.
Without the DEF head unit working correctly, the system may display inaccurate readings, trigger warning lights, or limit driving capability. It’s essential for maintaining emissions compliance and preventing DEF-related malfunctions.
