We know a Yeerk could control exterior things, such as blinking and such, so looking at them would be no more informative than staring down Hannibal Lector.
Things like heart rate however... are they based on the Yeerk's physical state, or the human's? For example, does heartrate increase based on the Yeerk's emotions or the humans? If it's the Yeerks, it should pass with no problem. The whole idea of a lie detector is based on how emotions affect you physically. A typical Yeerk sees humans as no more than animal hosts, so it shouldn't feel anything lying. It's just like when you tell a human, "State the sky is green." When they say, "The sky is green", they aren't really lying, and it wouldn't show up on the test.
If it's based on the human, well, the test would be failed instantly. The human would be so freaked out inside, as well as desperately trying to fail the test. So the test would be failed, most likely.
I'm leaning towards the fact it's based on the Yeerk, because controllers would be noticed far more often if they constantly had sweaty, clammy skin, as well as a high heart rate, all of which comes from constant fear or stress. So they probably could fool a lie detector, in my opinion.