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P0440

6K views 7 replies 4 participants last post by  tosterho 
#1 ·
OK I've changed the vacuum lines for fuel hose, replaced the NVLD lines and the stealership one at the canister. Changed the vacuum lines near Purge Control Valve and filter to throttle body. Changed the NVLD. Gas cap is relatively new as well and tests fine.

Per Torque, the Purge Control and all is functioning OK when I expect them.

Drive for a week or 2 and finally pop a pending P0440 and the next day pop the MIL on.

Took it in to a shop for a smoke test, it passes. Sealed system.

What else could it be? A sensor someplace that I'm not aware of or a fuel pump sending unit?
 
#4 ·
All vacuum lines have been swapped out. From the tank to NVLD, The 'Kit' of 2 horse shoe hoses and a stealership formed hose. The NVLD swapped as well.

The fuel filler shows little to no rust when looking up from under rear wheel.

Fuel cap is correctly breathing and holding vacuum. Replaced with spare just in case 2 months ago, same thing.

2 smoke tests 2 different shops, sealed and passed.

I did discover the PCV line hose at rear of intake was severely cracked, someone had already taped it once (not me and I'm original owner). So now I'm awaiting stealership to receive the line. I also stopped at Napa and picked up a new PCV since this is the original and does rattle on test. Could this leak be related?
 
#5 ·
Oh and I am thinking I might just swap the Purge Solenoid just for giggles since it and the canister are all that hasn't been changed out.
 
#6 ·
OK quick update. The little 3 inch hose from the PCV valve to the hard pipe back to the rear of the engine. I found some cracks so wrapped some tape, I knew it was a temp solution, but wanted to get the evap side fixed first. So having nothing to go by I decided to just go proper and fix the little hose, in hte process of removing the little hose, the other end suddenly stated flopping about. Found it was severly cracked and missing chunks of hose. Someone had previously wrapped tape around it already. I've never had an issue with the system previously as well. Hmm. I was told it's a stealership item only, so I had to buy the entire hose harness (grrr I just wanted the 2 rubber end bits).

Long story short, my STFT is now hovering about 0 (varies neg-pos but minimal).

Downside, I now have a P0440 & P0456. Previously last year or so I've fought this P0440 as the only code it gave.

So could a leaky PCV hose to throttle body effect EVAP Emmisions? I'm trying to understand why it now is giving a P0456. I plan to test the Purge Valve if I can rustle up the proper vacuum tester.
 
#7 ·
Huh, well today I was headed out to raise the fuel level to make sure I didn't drop below the minimum to run the test. For the first time this test has completed in a long time.

So should I go 3 Drive cycles or reset the codes...???

It does appear I was losing enough vacuum between the PCV and throttle body to help trip the P0440, per a quick chat with the stealership tech I spoke with.
 
#8 ·
I had that code a few times. Replaced the hoses and it went away. A year later it came back on so I replaced the purge solenoid and I haven't seen it come back. Hopefully you get it figured out please keep us updated!
 
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