P050F-Brake assist vacuum too low

[airline tech]

For Ref:

Item #13 is the Vacuum Pressure sensor that is reading the Booster Vacuum

Item #14 is the Vacuum Tube Assembly, incorporated into this assembly is an Aspirator Valve & Solenoid and when the Vac Pressure sensor reads low vacuum the solenoid opens and allows extra vacuum to be drawn from the booster.
(Vacuum On Demand)
The manuals really never cover it - but the tube assembly I believe also has a check valve.

The electrical function of the Solenoid will trigger codes: P103C / P103D / P103E
so that appears to be working normally.

With it being that this had a - Brake Assist system on it, I would say that there is a vacuum leak between the (Vacuum Tube) assembly and the Booster.
Check Connections as well as the (Booster Grommets) both upper and lower for the Pressure Sensor.


The Vacuum Pressure sensor is not generating any failure codes but still may not be reading accurately.

To test use scanner and read the Pressure PID, then pull the sensor and tap into the port with a vacuum gauge (do the readings match)

You can also isolate the Vac Tube Assembly -Using a Vac Gauge
Test at Intake Vac Port (Tube Inlet) and then Pull the Tube from the booster (and tap) tube side.
Do the readings match?

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[airline tech]

Hose / Tube Routing

 

[widnert]

Hose / Tube Routing

Thank you! I will be checking things this weekend. I am also betting that there is a leak somewhere but, never having installed one of the brake assist systems before, I was struggling to understand where all the connections were made. This really helps me understand the vacuum system on the truck.

 

[widnert]

Check the vacuum hose to the brake booster for leaks or loose clamps. Use the picture in post #14 for reference. Follow it back to the engine while inspecting.

Thank you! I was trying to understand where these brake assist systems connected into the braking system of the truck. Is there any other connection other than the one at the booster? Thanks again!

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