Apr 26, 2016 17887 - Brake Boost Vacuum System P1479 - 008 - Mechanical Failure - Intermittent Readiness: 0000 0001 Confirmed fix of Check Engine Light codes P1479 P0171 P0174. It's been one week since replacing the cracked vacuum pipes in and around the left side of the engine near the air intake filter coming off the intake manifold and that little silver. Dec 13, 2013 I hooked up a vacuum gauge and it shows the vacuum dropping off rapidly after the brake pedal is released and it slowly builds back up to about 25hg. Now if the pedal is pressed hard and released repeatedly by about the 4th release the vacuum gauge is near zero and the pedal is a stiffy.
![Brake boost vacuum system mechanical failure system Brake boost vacuum system mechanical failure system](http://www.capav.com/Audi/Engine/3_Engine.jpg)
Perform a short trip in Engine Control Module (ECM) (basic setting; display group 8 with ignition on and selector lever in 'P' or 'N')- Check hose setup to pump or from pump to brake booster- Perform output Diagnostic Test Mode (DTM) in Engine Control Module (ECM) to check whether vacuum pump runs or is activated.No personal experience with this - I just happened to have my manual open for something else.Looks like a leak in a hose or a bad pump. Both seem pretty easy to replace. No idea about $$$ for parts.