2016 Volvo VNL

Ive been having an issue with my truck for the last couple months with the air system. Every time I think it’s fixed, it starts acting up again. The “Air Dryer Malfunction” light is on. The primary and secondary tanks both build up to 140psi and the safety valve starts popping off a few times until it starts a slow leak that is clearly heard running 70mph down the road. It will seal itself back up at 90psi and start the process all over again. I’ve also noticed if the RPMs drop a little it will seal itself. I’ve taken it to the Volvo dealer on multiple occasions to get it fixed and a couple weeks later it starts it all over again. I’ve replaced the air compressor, the dryer, the safety valve in the wet tank, and an air pressure sensor in the wet tank since May 29th. Since the mechanics can’t figure it out, I thought I’d try asking some people who’ve had similar problems.

 

There hasn’t been any lines replaced to my knowledge.