I would at least attempt to clean the tube from the bottom (intake) side of the engine. Disconnect the tube at the intake (its tricky but you can do it with a 10mm open end wrench) and also unbolt it next to the oil filter and then you'll be able to use a pipe cleaner or something to clean the carbon deposits out of the intake side where they build up.

I did this in July or August and have put 5k miles on the car w/o having any reoccurence of code 5 or the CEL. I know most will recommend changing the tube with the updated part but cleaning it was free and I haven't had to do it since.

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Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE