However . . .
Just because the smoke machine finds a leak, do NOT assume the leak was the only problem
There are a few cars out there with one fault code, but multiple problems
Again, this is where verifying the repair comes in
After fixing the leak, you verify the repair. And it is at that time you might find it has more problems. And you realize you’re not quite done yet.
For example . . . the smoke machine finds the rotten gas cap, you clear the code and send the car on its way. But the purge valve can’t pull a vacuum, or the hose connecting the valve to the manifold is no good, or fell off. Soon enough, the car will have 2 consecutive failures, and the MIL we be on again
That’s where running the evap service bay test comes in. If your scanner is incapable of initiating the evap service bay test on a specific vehicle, at least drive the car under the appropriate conditions, so that the evap monitors run to completion
Or you could disregard what I said and take your chances
More often that not, you’ll probably “get away with it”
But that one guy might be upset and rightfully so. And he might tell plenty of people that your shop is lousy, as far as diagnosis and repairs are concerned. Might hurt your business