Hi all,
I have an intermittent issue with the evap. vent valve.
During the vacuum test, it is supposed to stay closed, but it does not.
The valve does not stick and operates fine when 12V applied, I have steady
positive at the terminal but do not get that "switched" ground which suppose to be sent to the valve by ECU.My electrical schematic for some reason (may be
the wrong one)shows different color coding.
My question is:does this "switched" ground come directly from the ECU during the vacuum test, or goes through other component which might be defective? Also,if it comes directly from the ECU, what are the pin # and the wire color?
Thanks.

 

Just went through this 5 or 6 weeks ago. My valve operated fine "on the bench". So I replaced elbows and tubing from the tree to the valve. Still got codes. Finally replaced the valve. Works fine now. I noticed that the valve got very, very hot next to the radiator. I'm thinking that after a couple of hundred lousy miles it ceased working when hot but would work when cold (room/garage temp). My mechanic just laughed and said they all go bad eventually and he just changes everything at once. I should of let him.

By the way, do you have the round one (98s are supposed to be round) or the square one (like mine).

 

You are referring to the purge valve, on the fan shroud.I am talking about the shut-off vent valve,by the charcoal canister,in the rear.
The purge valve in my car is square, operates fine.

 

Sorry!