The brake line to a wheel brake cylinder of your motor vehicle is leaking heavily. How can you detect this issue?

Your selected combination is correct because it includes all the key indicators of a leaking brake line.

1. The noise generated by escaping compressed air is a direct indication that there is an issue, as it highlights a break in the system.
2. The pressure warning indicator is designed to alert the driver to any loss of pressure in the braking system, which is critical for safety.
3. Reduced braking action while driving is a tangible symptom of the problem, as it indicates that the brakes are not functioning optimally.

In German traffic laws, a safe and functional braking system is paramount for vehicle safety, and recognizing these signs helps prevent accidents. Being aware of these indicators is crucial for timely repairs and maintaining compliance with vehicle regulations.