Practice question

What happens if a modern Euro 6 commercial truck runs completely out of AdBlue (DEF) fluid while driving?

  1. The engine control unit (ECU) triggers an emissions fault warning, enters torque-derate (power reduction) mode, and limits restart capability until refilled
  2. The engine explodes immediately due to excessive heat
  3. The truck switches automatically to run on compressed air
  4. Nothing happens; AdBlue is completely optional for engine operation

Answer: A — The engine control unit (ECU) triggers an emissions fault warning, enters torque-derate (power reduction) mode, and limits restart capability until refilled

The correct answer is shown above. Try the full quiz for additional practice.

Practice more: BiH Theory C Practice Questions - Bosnia and Herzegovina Driving Theory Test - Category C (Truck & Heavy Vehicle) Exam →