Hi Folks,
Anyone experienced the need to replace the front & rear system valves(?) for this problem. New gas cap didn't take care of this so the system valves are usually the next course of action. (I've been told by 2 mechanic's). Estimate a couple hrs labor + parts. I may go look for the parts if I can ID the correct ones needed for my 2002 SC.
Thx for any info on the subject you may have.
Max

 

I had to replace a couple of the vacuum lines - old, brittle, cracked.

Based on readings here on the forum, maybe first take a look at the one on the driver side. Seems old motor mounts can cause enough movement to pull off/tear the vacuum line that runs from fender side to engine.

 

There was a thread on this topic about a year ago. Try searching it in the SC430 forum. From what I remember, the OP was told to replace the valve in the engine bay first, as the one in the back, near the gas tank, was much harder to access. I think the new front valve cured his trouble light. However, as mentioned above, it could just as likely be a cracked, broken or disconnected vacuum hose.

 

I agree. Cracked hoses are VERY common on the SC after about 10 years.

The right thing to do is buy the preformed hoses from the dealer, but you can also get bulk vacuum hose and make your own.

Do a google search for "ClubLexus.com SC430 P0440"

 

FWIW ..... I ended up taking car to dealer for smoke test. In the long run it saved $ for what other mechanics would have missed without the test (approx $200). Needed seals and hoses on upper side of gas tank $1,500 but finally fixed and engine light out and emissions test passed.