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Canister Purge Valve Idle Vacuum

Old 09-13-2017, 07:35 PM
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Default Canister Purge Valve Idle Vacuum

Hello all,

I have a check engine light on my 2007 CTS 2.8L for P0496 which points to the purge valve in the EVAP system. Heres what i have done to troubleshoot:

Replaced the purge valve with a new one from Auto Zone. Code remains. At this point i was unsure what to do so I took the car into the shop and they performed a smoke test - I was told they found a leaky purge valve. I took the car back and got the part replaced by Auto Zone, since it was brand new and believed to be faulty. I installed the new purge valve and the code remains....

With the engine warm and at idle I disconnect the hose going from the purge valve to the engine intake, engine starts to sputter and i can feel a vacuum on the hose - so i know the engine is pulling. Reconnected that hose. Now I remove the hose going into the purge valve. I can feel a vacuum and hear the pulses. With this hose disconnected I removed the electrical connector and the pulses stop, as well as the vacuum.

My question is should the purge valve be open during idle? From what i have read it should be closed. None of the electrical wires look to be frayed and I'm hoping the shop was accurate with their smoke test, so there are no leaks elsewhere.

Any ideas? I'm not sure where to go from here.
Old 09-13-2017, 08:25 PM
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Is it possible to move this thread to general tech?
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