CM871: lost boost

[RMezaJr]

I was on Interstate 5 Southbound, going up the grapevine when my boost gauge dropped to 0 and started hearing a hissing sound. The check engine light came on, don't remember if it came on during or after I noticed the boost gauge. Pulled off to the side and looked for anything that looked out of the ordinary, everything looked fine. I would only hear hissing while in motion so I assumed the gauge was powered by air, my tanks remained at capacity and at that point the engine brakes still worked. When the hissing stopped, the engine brakes stopped working. I got the following error codes but seem to be inactive.





What could have caused this? Is this a safety measure from overboost?