I am hoping I am not the guinea pig on this one and have a leaking canister! Fingers crossed that smoke test does not produce a leak there. If no leak is detected anywhere, I will pull the VSV to see if it is working properly, and go from there.

 

Using the diagrams above, I was able to trace the lines from purge valve to the airbox, checking again to make sure all is well. One valve I wasn't aware of was the Canister Closed Valve. Upon inspecting that area, I found that the connector was not connected to the valve. An A Ha! moment. I reconnected it, hoping this would be the issue, but the MIL and CEL lights are still on after a short drive.

Will this eventually reset, should I erase codes and see what happens, or go ahead with smoke test tomorrow?

 

I decided to ditch the diagnostic today and reset the codes. Prior to resetting, I did another read, and only one code was present, P0455, large leak. 0446 and 0441 went away after reconnecting the switch and driving the car a bit. This weekend I plan to replace all the hoses running from the purge valve to the throttle body. If the past repeats itself, and there is still a problem, I should know by next Friday.

 

Your original post stated: "This issue comes on the heels of a new starter (Lexus dealership), and new radiator (DIY)." Did you or the dealer disconnect the electrical connection to that switch?

Now knowing this, I strongly recommend that you do not change any hoses. After having cleared the codes, you should wait to see if any codes re-appear.

 

I've been trying to remember if I did when I moved the air box out of the way for the rad install. I did not pull the box out, but simply moved it out of the way. It must have come off in the process (or I did disconnect it and forgot).

Timing wise, the first CEL appearance was a week after rad install, same time span as the next 2 after reset.

 

Given your discovery, now is when you don't want to start throwing parts at it. MIL codes have different cycles and running times. If it took a week for the codes to return on 3 separate tries, wait a week (at least), as long as your upcoming driving plans are like the last 3 weeks. And, you can rest easier with confidence that it's not likely the canister.

 

Tom, thank you for the recommendation. A small update from the weekend. I had time to inspect the hoses a bit more, and noticed some rigging done by the dealership when replacing the starter. The PCV hose connecting the air intake box to the passenger side valve cover (wrapped in sea foam) had been wrapped on each end with electrical tape due to splits in each end. Rather than replace the hose, they wrapped each end. I removed the hose, unwrapped each end, and found an entire chunk of the valve cover end came off with the tape. On the intake box end, there was a long split in the hose. I did end up replacing this hose because of how badly damaged it was. Whether or not this was a symptom of my issue remains to be seen, but between the switch being reconnected and replacing this hose, I am hoping it has been put to bed.

 

It's been 8 days since resetting codes, and no alerts or codes have come back.