Short version.... Wife's 01 XC70 recently caught the wonderful P0442 code with associated Checkj engine light. I reset the light several times, but it comes back, so I know it is a legitimate issue.

Longer version. I recently changed the gas cap to see if this would help the issue. No dice. You clear the code and a few days (depends on miles driven) the code comes back. I will be changing the shockes and struts on the car this weekend, so it is a good time to chase this down and fix it.

I have read all the articles I can find via searching for this issue, but could anyone give me a good step by step way to chase this down? I plan on checking the hoses from the evap valve on the radiator shroud to the manifold, and all the way back to the fuel tank.

Any tips on this or where else to chack.

Many thanks,

Glenn

 

First remove the valve and try to blow through it if you can it is bad.

 

That's a place to start. I'll do that this weekend.
Thanks Tech

 

Keep us updated.

 

Well, I pulled the evap valve off the readiator shroud, disconnected the electrical connector and both hoses. Tried to blow air through it and no air would pass through so I assume the valve is good.

Glenn

 

Yes it is good most likely but it might be sticking open at times causing the code. If there is no leaks anywhere you might want to get a new valve.

 

Good idea, I already replaced the gas cap, and the hoses seem to be good, so I'll try the valve next. I'll probably order it from Groton. My son just came home about an hour ago in the 850 and a rock hit the left headlight lens and starred it (glass lens) so since I am ordering a new lens, I'll order the evap valve too

 

Ok,
New evap valve is in....Check engine light still comes on. So it looks like I am down to hoses to check. Is there anyway to check them outside of pulling them all off? Can I use a vacuum pump to see if they leak, or?

Thanks for any help

Glenn

 

I would try to add pressure somehow but not to much. A vacuum pump would take way to long to get it into vacuum.

 

Well, I might be able to disconnect the hoses from the evap valve, and use my air compressor set at about 10 PSI to inject air into the lines. I might be lucky enough to hear or feel a leak.... What do you think?

Glenn

 

Keep it at about 3 PSI or so. Another thing you have to do is climb under the car and find the charcoal canister and pinch off the bigger hose that looks like a J before adding pressure.

You have to be careful to keep the pressure at about 3 PSI or so.

It will take a few minutes to pressurize the system then you can pinch off the hose by the evap valve and look for the leak spraying soapy water on the hoses.

If there is no leaks at all anywhere look for the valve that is on the J hose. You can add power to that then unpinch the J hose and see if it still holds pressure if it does not then that valve is bad.

 

Sounds like a plan. I wll do that on Monday after work (that will be the next time I can work on the car. Where exactly under the car is the charcoal cannister. I never really looked for it before. Also, 3-5 Psi is no problem, I have a decent regualtor on my compressor.

Thanks tech, I truly appreciate the advice

 

It might be over the rear suspension by the trunk area. That is usually where it is. But they moved it around a few times.

Your welcome anytime.