I feel that this needs to be translated quite freely in order to work in English.

I construe the original literally as follows:

But it is worth asking oneself in relation to what values relevant to the examination work times [...] are going to be checked.

I read "valores relevantes para el examen" as meaning "values that are relevant to the examination", rather than "relevant values for the examination". I believe "examen" refers not to an exam (a test that drivers have to pass) but to an examination in the sense of an inspection.

The Spanish is rather cumbersome and anything approaching a literal translation is going to be very cumbersome in English. All it really means, I think, is what criteria they are going to use as a reference standard against which to measure the times they are going to examine. "Valores", with "en función de", implies references standards or criteria (a "baremo"), and I think "values used as criteria" or "standards" would make it clear.

I don't think "relevant to" actually needs to be directly translated; all it really means is the values that are going to be used in the inspection.

So the whole thing might run more or less like this:

But the question is what values are going to be used in the inspection as criteria / standards against which to assess..."

Or you could probably cut it down to this without significant loss:

But the question is what criteria / standards are going to be used in the inspection to assess..."

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Note added at 15 hrs (2013-09-29 12:05:14 GMT)
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Just spotted in error in the answer line: I meant "what values are going to BE used...", of course.