Question What may happen if the exhaust system is not working properly? Answers Poisonous fumes may enter the cab. Poisonous fumes may exit the rear of the muffler system. It may prevent proper steering. It may cause problems if the trailer is fully loaded. Explanation A broken exhaust system can allow poisonous fumes to enter a vehicle's cab or sleeper berth. Be sure to regularly check your exhaust system for defects. Take a FREE Practice Test Now This questions appears in the following tests: Delaware Knowledge Test Class A ,