3DE38AB775414931A28E894C74A608E2.jpg 3DE38AB775414931A28E894C74A608E2.jpgDoing a purge and seal evap test on a 2021 Silverado with the 2.7 Turbo. As you mat know the purge valve is located on the atmosphere side of the throttle valve so there is no vacuum. Instead this vehicle has a small vacuum located on the intake manifold to draw vapors out of the canister. My question is, shouldn't the pump be commanded on during this test ? As you can see in the screen shot it is not being commanded on. The puge valve and vent vent valve are being commanded and are operational, without vacuum though the test is a mute point. Is this a snap on error or a GM oversight. The code I had was P0446 and was a plugged or stuck vent valve which I replaced and solved the problem. Just wondering about the purge and seal test. A larger image below ?
-
-
PXL_20260618_152936532.jpg Maybe this screen shot of the function is a little clearer. The other was a download from Altus, not very clear
Comment