Not always, a small air leak and a lambda that is still giving an out put but wrong might not be enough to put the light on. This is why it is useful to look at live data.
An air leak will obviously lean off the mixture and this should show up as the compensation should be quite high trying to get it back to where it should be. Look at the swing on all of the lambdas, they should all have the same amount of swing. You can move them from side to side if you want to test them.
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