Most likely. Or your engine is not producing any vacuum, which is unlikely.

Of course, a completely severed vacuum line that leads to the manifold will suck in enough air to nullify the vacuum, but that also leads to other conditions that will produce a check engine condition.

Verify your ABS codes in A-3. Make sure your ABS light turns on when you turn the key to pos II, before engine start.

And replace the check valve, not super expensive!

Klaus
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Why are Volvos so endearing? Its just a car.