Troubleshooting a trailer that takes to long for air bags to air up. Video goes over how air is delivered to air bags with information about height control valve and how the pressure protection valve works, or in this case, failed.

* It's worth noting that in the 10 years I've been working on trailers, I've only replaced 3 other pressure protection valves, and all 3 times it wasn't the problem. PPV are pretty robust and rarely fail. Usually it's another valve, air leak, incorrect plumbing or kinked airlines.