P0440 Touble shooting

[eppoh]

My 97 legacy is throwing a P0440 code. Last time I had this on another car it was easy- hole in bottom of hose at cannister.

 

This one not so. Haynes manual is generic and vague. Can someone point out where these different lines are under the hood to start with?

 

I have already checked the fuel filler neck and the gas cap was checked recently at inspection.

 

Can that little valve on the cannister cause this code, and how is it checked?

 

Thanks

[OB99W]

These EndWrench articles might be helpful:

http://www.endwrench.com/current/02SpringInsiderInfo.pdf

http://endwrench.com/pdf/fuel/MoreP0440TipsInfoW00.pdf

http://www.endwrench.com/pdf/fuel/FtEvapEmissionTestW00.pdf

[eppoh]

Those endwrench articles are good at explaining how the system is supposed to work, helpful- I suppose, if you work in a dealership with expensive Subaru test equipment,. Not much help for the backyard mechanic.

 

A good start for me would be just identifying which hose is which in the engine bay and how to test them, as well as how to test that switch on the Evap cannister.

[naru]

Page 242

http://www.finleyweb.net/JonsStuff/SubaruDocumentation.aspx

[OB99W]

Those endwrench articles are good at explaining how the system is supposed to work, helpful- I suppose, if you work in a dealership with expensive Subaru test equipment,. Not much help for the backyard mechanic.

The sophisticated test gear helps, but isn't a necessity. Understanding how the EVAP system operates is key to fixing it.

 

 

 

A good start for me would be just identifying which hose is which in the engine bay and how to test them, as well as how to test that switch on the Evap cannister.

Coupling the under-dash TEST connectors will cause the solenoids to cycle with the engine running. Look at the label on the underside of the hood for what hoses and other parts are in the engine compartment. Using those two pieces of information, you should be able to at least verify the operation of the purge control solenoid by determining whether vacuum is being applied.

Edited March 1, 2010 by OB99W
Corrected spelling!

[eppoh]

The sopisticated test gear helps, but isn't a necessity. Understanding how the EVAP system operates is key to fixing it.

 

 

 

 

Coupling the under-dash TEST connectors will cause the solenoids to cycle with the engine running. Look at the label on the underside of the hood for what hoses and other parts are in the engine compartment. Using those two pieces of information, you should be able to at least verify the operation of the purge control solenoid by determining whether vacuum is being applied.

 

 

So, I would be able to hear the solenoid cycle? Where is it located?

 

That stick diagram under the hood looks like greek to me.

[eppoh]

Page 242

http://www.finleyweb.net/JonsStuff/SubaruDocumentation.aspx

 

page 242 of which file?

[OB99W]

So, I would be able to hear the solenoid cycle? Where is it located?

 

That stick diagram under the hood looks like greek to me.

There are three solenoid valves. I mentioned the purge control because the hood label shows it. As to their locations...

 

 

 

page 242 of which file?

...download the last manual on the page that naru linked to and look at the On-Board Diagnostics section for P0440.

[eppoh]

Okay, thanks. Any idea where that Pressure Control Solenoid valve is located? I can't tell from the drawing in the manual, and it does not say.

[OB99W]

Okay, thanks. Any idea where that Pressure Control Solenoid valve is located? I can't tell from the drawing in the manual, and it does not say.

The engine emissions control section of the manual probably has more detail. The purge solenoid is under the intake manifold, the rest are usually back near the canister.