2012 F150 EcoBoost. So I had a noisy brake vacuum boost pump, the one behind the driver side headlight. It was super noisy and always running, plus I had a "check brake system" light come on. I took it to a shop for a diag, they determined it was a failed brake vacuum boost pump, said that would clear the light. Shop quotes me like 2 Gino's + to change it out parts and labor. I decided to order an OEM pump on rock auto and swap myself after a YouTube video, seemed simple. So I swapped it out, turned truck on to verify it was working and it was, operating much quieter and was cutting out unlike the other one that ran constantly. BUT... the check brake system light came on again, and stays on. Now what???? I'm not a mechanic, I read some other posts and one guy said brake vacuum solenoid, one said their issue actually ended up being a speed sensor which threw that code.

I don't want to go back to the shop yet. Especially since I would have wasted all that money hiring then and ended up in the same place.

Pump needed a swap anyway so that's fine. But obviously I have another problem.

Please help.

 

The ABS module will have a code in it. You will need to see what that code says.

 

Are you getting a stiff brake pedal while this fault is active? The brake system vacuum is tied to your 4wd vacuum which may not cause issues with the 4wd system as in my case. I was receiving the "check brake system" fault followed by a stiff brake pedal and ended up finding my IWE vacuum hose was pulled off the hub causing a vacuum leak in the system. There's also a check valve on those lines up by the brake booster which could be bad. I read a post from someone saying the check valve was their issue which sent me down the IWE vacuum path and found my problem. It's worth looking into though.

 

I'll see if can borrow a scan tool!

 

No stiff brake. The brake has worked normally 98% of the time. Now I did have a couple instances where going slow the brake actually went soft and made a sound, kind of like the ABS sound when you're say sliding on ice. I replaced the vac booster itself along with the hose assembly, it came as a kit. I believe the hose has a couple check valves in it so those are new now. Now there is a sensor of some kind that goes into the booster assembly, the round thing on the firewall. That is not new. See pics.

This is what comes in the kit, vacuum pump and hose.

This is the sensor going into the booster assembly. That was not changed.