Hello everyone I'm new to the forum, but not to GM. Right now I'm riding 2008 Chevy Impala...

I'm having an issue with this P0556 code brake booster sensor.. Now I changed the pressure sensor, the vacuum lines and the code will not go away. I unplugged the battery for 2 whole days. I cleared the code with my snap-on OBD still came back on. PLEASE PLEASE ANY CLUE ON WHAT IT COULD BE... PLEASE HELP IT'* DRIVING ME CRAZY.

Should probably check wiring between the sensor and the PCM.

Have you changed the one-way valve?

I will check the wiring this weekend. I have not changed the one-way valve, so I will add that to the list for this weekend. I have heard that the power steering pump could be the cause as well. And thoughts on that?

That'* if you have hydroboost (hydraulic brake booster driven by the power steering pump). If your 2008 Impala is stock then you don't.

If you do, you have the only one and your car is extra collectible.