Strange noise coming from my rear.

[KBTerra]

When I got home from work today I walked around to the back of the Xterra and I heard this buzzing (or more like a sign wave tone) on the passenger side rear. I looked underneth and all but can't tell where its coming from. The X has of late been throwing a P0420 code. She runs perfect so I just clear the code till I can deal with it. Any ideas what might be causing this noise I'm hearing? I'm thinking it could be a air leak making that sound. IDK.

 

[Macland]

Sounds to me like your X has gas! Badum tsh!

 

[KBTerra]

Sounds to me like your X has gas! Badum tsh!

I was waiting for something like that. lol

 

[Muadeeb]

I think a small evap leak is possible, but it should be throwing a code. There may be a hose somewhere that's collapsing under vacuum, then letting it out when it's released.

Other thought is a valve going, as I've heard electronics whine before. There's not a lot of things in the back half of a 1st gen, so options are limited.

Sent via wild ferrets on crack

 

[J Everett]

Probably the evap purge control valve or solenoid.


BTW, the code you're getting is for a catalytic converter or oxygen sensor. I can't remember which.

 

[KBTerra]

Yeah the code is a Catalyst code. But it's said a leak can trip the code too. Today I got a 1490 code the Vacuum Cut Valve Bypass Valve. So that narrows it down a lot.

 

[Cyclemut]

Sounds like the gas tank is venting. Loosen your fuel cap, see if it goes away. If the noise does go away, then you might want to replace the gas cap.