M939 Air system Diagnostics - No air pressure/low building pressure

This is a diagnostic procedure of when your truck will not build any air pressure at all. OR will not build air pressure above a certain PSI - like 40 or 60psi.

This is where you start. Add your gauge to the compressor first to see what the output is. Low pressure indicates a unloader or compressor problem. If it is pegging the gauge out then you know you have to move down the discharge line to find out where you are dropping the pressure at.

Видео M939 Air system Diagnostics - No air pressure/low building pressure канала Wes Simpson