What happens to a combination vehicle's braking if the ABS fails completely but the regular air brakes are undamaged?

Pick an answer

1. The parking brake also automatically stops working entirely whenever the antilock braking system fails
2. The vehicle loses all braking ability immediately
3. The service brakes still work and stop the vehicle, but wheels can lock up under hard braking without ABS to prevent it
4. The engine automatically limits speed to compensate

Correct!

Not quite. The correct answer is highlighted.