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I’ve been working on various things that could be causing this code on my car. I replaced the VSV near the vapor canister in the back. I fixed some evap lines near the radiator fans, and verified that the VSV there gets power.
Any other ideas before I replace the canister? Are these valves related to the evap system and the p0446 code?
Also, if I’m testing the connectors (the plugs), do I need to take off the negative battery cable?
Thanks!
Last edited by jhomer42; May 17, 2025 at 04:12 PM.
EVAP System in Toyotas is as much of a wonderland for me as Bosch K-Jetronic, all you can do to diagnose it is systematically go over the entire system and check everything off one by one. If there is one thing I am always certain of, it's that every year or so my 2000 ES300 will throw some variation of an EVAP Code, and every time the cause for it will be different than it was last year, at this point I've replaced just about every solenoid and every Vacuum Line I could reach.
The latest update in the saga was one of the Membrane Valves on the Canister, it was damaged in some way and created a weird Clicking, and later Whining Sound, here is a thread about it. Since I was in no mood to pull the Subframe off to access the Canister, I ended up replacing just that Valve, taking it off one of the spare Charcoal Canisters I've had laying around, which wasn't even suited for ES, but after some maneuvering with the Vacuum Lines it fit in there without too much difficulty. Seems like it's holding up so far, so you too might as well try replacing just that valve before tearing into the Charcoal Canister as an assembly, which would be quite a lot of work, though Toyota doesn't sell them separately, so you will have ti find one at the Junkyard.
Originally Posted by jhomer42
Are these valves related to the evap system and the p0446 code?
Not at all, the Left Red VSV is for a ACIS System, basically a Variable Length Intake, the other is for the Throttle Body.
Originally Posted by jhomer42
Also, if I’m testing the connectors (the plugs), do I need to take off the negative battery cable?
Well, depends on what kind of test you want to run, but trying to find power in the Connector with the battery disconnected will get tedious quite quickly..
EVAP System in Toyotas is as much of a wonderland for me as Bosch K-Jetronic, all you can do to diagnose it is systematically go over the entire system and check everything off one by one. If there is one thing I am always certain of, it's that every year or so my 2000 ES300 will throw some variation of an EVAP Code, and every time the cause for it will be different than it was last year, at this point I've replaced just about every solenoid and every Vacuum Line I could reach.
The latest update in the saga was one of the Membrane Valves on the Canister, it was damaged in some way and created a weird Clicking, and later Whining Sound, here is a thread about it. Since I was in no mood to pull the Subframe off to access the Canister, I ended up replacing just that Valve, taking it off one of the spare Charcoal Canisters I've had laying around, which wasn't even suited for ES, but after some maneuvering with the Vacuum Lines it fit in there without too much difficulty. Seems like it's holding up so far, so you too might as well try replacing just that valve before tearing into the Charcoal Canister as an assembly, which would be quite a lot of work, though Toyota doesn't sell them separately, so you will have ti find one at the Junkyard.
Not at all, the Left Red VSV is for a ACIS System, basically a Variable Length Intake, the other is for the Throttle Body.
Well, depends on what kind of test you want to run, but trying to find power in the Connector with the battery disconnected will get tedious quite quickly..
P0446 EVAP Code Lexus ES 300 1999
