Here we have a 2012 GMC Acadia with a check engine light on and sometimes a rough idle. Let’s check it out.
We scan tested the vehicle and found the codes P0496, which indicates EVAP system flow during non-purge.
The EVAP system is designed to prevent fuel vapors from entering the atmosphere, and it consists of various components.
Starting from the rear of the vehicle, we have the gas cap attached to the filler neck, which leads to the gas tank. Attached to the gas tank is the vapor canister connected to a vent, along with a pressure sensor at the rear to monitor the system’s proper function.
Lines from the rear of the vehicle run to the front of the engine, where the purge valve is located to provide the system with vacuum.
If any of these components are not sealed or working properly, it can trigger a check engine light with an EVAP code, as in our case related to the purge valve.
The purge valve on this vehicle is attached to the intake and opens and closes to apply vacuum to the EVAP system when commanded.
The code description indicates that the valve is sticking open when it’s not commanded. To test this, we can disconnect the valve and check for vacuum, which in our case confirmed a faulty valve that needs replacement.
Replacing the valve is a relatively straightforward process and should resolve the check engine light issue.
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What do the codes P0496 mean for a 2012 GMC Acadia?
The code P0496 for a 2012 GMC Acadia indicates an issue with the EVAP system, specifically related to flow during non-purge.
What components make up the EVAP system?
The EVAP system includes the gas cap, filler neck, gas tank, vapor canister, vent, pressure sensor, and lines leading to the front of the engine where the purge valve is located.
How does the purge valve function in the EVAP system?
The purge valve in the EVAP system is responsible for providing vacuum. It opens and closes when commanded, applying vacuum to the system. If the valve is sticking open when not commanded, it can lead to a check engine light with an EVAP code.
How can the purge valve be tested for issues?
The purge valve can be tested by disconnecting it and checking for vacuum. If vacuum is present when it shouldn’t be, the valve is faulty and needs replacement.
How can the faulty purge valve be replaced?
The faulty purge valve can be easily replaced by removing the bolt, sliding out the old valve, and sliding in the new one.