P0400 disappeared?

[rxm6]

I recently acquired a p0400 code. I cleared it and it would come back in about 8 cycles. So I let it be with plans to clean out the egr when i had some time. After about 2.5 weeks, the code went away and hasn't come back since.

I'm excited that my car fixed itself, but I don't understand smog crap enough to know if i should leave it be or do something preventative about it or even what would cause it to go away. I was under the impression that a blocked egr needed to be cleaned. Can it clean itself?

[maxnix]

Cleaning TB, EGR and IAC valves, plenum and ower runners is always a good idea. On the VH41DE, the often obstructed EGR tube in the plenum requires the latter's removal.