afanboy

My LS400 has run perfectly for the ~20 years I've owned it, except for the pesky evap codes (in the P044x group) that always came up after about 50-100 miles of driving. I'd clear the code and it would come right back a few days later. I had never bothered to get it smoke-tested and just kept clearing the code.

I went out of town and left the car sitting on a battery tender for almost six months. When I came back, the engine had the characteristic sound of failed VVT solenoids. I had the mechanic replace the VVT solenoids. All is well.

And... it's been almost a month, and about 1,000 miles of driving, since the new VVT solenoids, and I haven't seen the evap codes come up again, since we replaced the VVT solenoids. The check engine light is fine (does come on during startup check).

Do you think

1. VVT solenoid malfunction was causing the evap codes, something with the timing of the exhaust/intake air?

or

2. Mechanic must've incidentally touched something while doing the VVT job that stopped the evap leak?

or

3. Sitting for six months somehow sealed whatever was leaking in the evap system?

Or something else?

For me, it's no longer an issue, because my car is running great and there are no evap codes, but maybe this answer would be useful to others experiencing evap codes.

LeX2K

In theory oil control valves should have nothing to do with dreaded EVAP codes. My gut says a vacuum line of some sort was not secured properly and fixed by your mechanic as a side effect. Another theory is bad solenoids caused a rich condition which was harder for the system to deal with but that's a stretch.

afanboy

Mechanic says he didn't consciously fix anything but the solenoids.

timmy0tool

iTrader: (7)

does your car sit around often? 6 months of sitting is a lot. i've found the main culprit for EVAP codes is the gas cap (typically for small leaks). perhaps you just gassed up and cranked the cap? there is no direct correlation as you suspected.