P0441 Parts Cannon Running Low

I’m running low on parts I haven’t thrown at this P0441 Evap incorrect purge flow code.

I used a smoke machine and couldn’t see anything coming out of the system.

So far I’ve replaced the following with OEM Toyota parts: gas cap, purge valve, charcoal canister, corrugated flex hose that attaches to canister, and vacuum line from intake to purge valve.

Any ideas on how to diagnose this properly? Or any other parts I can try throwing at it?

Could the vacuum switching valve be the culprit?

2007 4.0 DCLB 4x4

 

Looks like yes the Purge VSV/circuit is the primary culprit according to the service manual. You said you didn't see any smoke so maybe it's stuck closed.

 

Have you verified the Purge VSV has Power on the Blue/White wire and put a test light across the pins and made sure the ECM can turn it on?

Since you don't have a leak (P0455/P0456) it can't be much of anything but the valve, a plugged line, valve circuit, or the driver in the ECM has failed and can't turn on the valve.

 

I haven’t checked the blue/white wire for power. Thanks for the tip, I’ll check it this evening.

 

In case this helps - not sure what year / engine, but this is from the 2013 FSM. P0441 is for the code, evap is the inspection procedure with chart and process in there.

 

Guess my post was too vague

 

didn't notice the last line - so applies (at least engine type - not sure what, if anything changed in evap system between years)

 

I added the last line after reading your comment. Thanks for the info!

 

This was on a Corolla but exact same system, Ivan (PHAD) diagnosed a P0441 that had the parts cannon unloaded on it.

https://youtu.be/obB1uuGfoQI?si=h9ZANm0culVBtAar

https://youtu.be/EBPDc2tMtoY?si=3z5IJn2xWjBwcnd5

 

I have 12.5 volts at the blue/white wire on the purge valve with key on.

 

Have you verified the ECM can turn the Purge VSV on? If not that would be my next step.

 

What’s the best way to do this?

 

Using a bi-directional scan tool to command it on is the best way, otherwise it's a crap shoot because the ECM only commands it on when certain conditions are met.

 

As @Dm93 states, just because you have voltage at the valve doesn't mean the valve works. Below is how you can test the valve for resistance (indicating the coil of the valve isn't shorted or broken) along with testing the valve manually by applying voltage. If you have something like a Power Probe, it works great for stuff like this, but you can also manually apply battery voltage via jumper wires.

 

This is great, thanks for sharing. I’ll try it.

Is there a similar troubleshooting procedure for the vacuum switching valve at the back of the intake manifold?

 

as far as i know, there is no "manual" test - the switching valve has its own code is something is wrong (P2420). I believe to test it, you use a Techstream or similar bidirectional to initiate the test for P2420 and it gives you the result.

 

Wow, I knew this code was a nightmare, but I hadn’t thought of the ECM driver being bad.

 

Should be no need to test that VSV, it's for the ACIS not the EVAP system.

 

Just checked the codes again and I now have P0456 (Evap leak detected, very small leak) and P0441

 

Well your gona have to do some testing and determine if:

You have a leak.

The purge valve is working and the ECM can control it.