2022 Perterbilt 579 Air leak

If it’s only doing that while driving down the road, and building air ever 3-5 minutes, it could be a brake can or something along those lines.

 

Or an air line running to the brake cans somewhere could have a small hole in it. Release tractor brakes. While stopped somewhere, set trailer brakes, then get out and listen for leaks on the truck. Then set tractor, release trailer, and listen for leaks on the trailer.

 

I13 isn't anything to worry about. You carry a tire gauge I hope? And a spray bottle of soapy water isn't a bad idea either but this is easy to find out in the wild.

 

This is good to know. Video is 36 seconds.
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A leaking tire on a trailer with an automatic tire inflation system (like Meritor MTIS) can be detected by a warning light that illuminates on the trailer. The light signals that the system is delivering an excessive amount of air, indicating a leak in the tire, a system component, or a high wheel-end temperature.

 

I’ve got a newer Pete 579 18-speed, and it does the same thing. It’s the way the ECM has been programmed at the factory. The sensor tells the compressor when to turn on, as it reaches a lower air PSI threshold. As long as the PSI builds right back up, nothing to worry about.