'08 Base - Air Pump operation problem/question?

I have the notorious EVAP codes that have been intermittent for years now. But a few months ago, the problem got much worse and now codes are set almost instantly after getting cleared. The "Check the Gas Cap" message comes up about once in ten trips.

The thing I noticed almost immediately once the problem became persistent, was the silence. Usually my air pump belts out a high-pitched scream when the car first starts. Now it doesn't seem to come on every start. But, it still comes on sometimes.

So, is the air pump the likely culprit or does the pump not come on under certain conditions (like a loss of vacuum, faulty solenoid, etc)? I know that an A/C compressor won't engage when there's not enough pressure in the system. Is this a similar situation?

Thanks,
Doug

Air pump has nothing to do with evap codes...two different systems....

In warm weather, if your coolant is above a certain temp, it will not run at all....tends to run more in the colder months, because the coolant temp is much lower....

Sounds like you have a P0440 or P0442.......if not the gas cap, then could be vent or purge solenoids, a leak, pressure sensor, etc...

Only way to know for sure is a smoke test.....

Air pump has nothing to do with evap codes...two different systems....

In warm weather, if your coolant is above a certain temp, it will not run at all....tends to run more in the colder months, because the coolant temp is much lower....

Sounds like you have a P0440 or P0442.......if not the gas cap, then could be vent or purge solenoids, a leak, pressure sensor, etc...

Only way to know for sure is a smoke test.....

Thanks for the duh moment. I know the pump's role in the secondary air system. But for some reason I thought it had something to do with EVAP as well. I don't know why.

Yes, I've had two codes for a while p0449 and p0455 and I was fairly certain they were EVAP related. But I just checked the codes again to make sure and I have a new one to add as well p0106 (Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem.) I don't think the air pump interacts with that either. But now I wonder if there is a vacuum issue related to both systems? Ughh.

The hits keep coming. Thank God I can do most repairs becuase this car has so many problems, I'd call it quits by now if I had to pay a mechanic. This is a '08 Grand Prix with 90k miles. My old '98 Grand Prix had 185k on it when I traded it in and that car was still immaculate (except for the power windows which broke every 6 months or so).