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P0440

Posted: Sat Feb 03, 2018 12:07 pm
by racer12306
A “friends” car has been throwing this code for probably 3-4 years.

Is that ok?

Last time emissions came up the computer may have been reset and then driven for a couple weeks keeping the gas above 3/4 tank until the readiness monitors were ready.

Re: P0440

Posted: Thu Feb 08, 2018 1:07 am
by BlackRoseRacing
The large evap leak could be one of the larger diameter rubber hoses on the evap canister which also houses the leak detection pump. It could also be a rotted fuel neck.......
"Technically" it's not safe due to the gas fumes that may leak from the hoses, BUT if the "friends" car has made it this long with the leak not causing further issues I would not worry to much about it (especially if you don't smell gas) But also keep in mind that when the check engine light is on, the pcm runs in a different spark and fuel map to help keep the motor in "safe" operating conditions.
If you are able to get the car up in the air on a lift, take a look at the hoses and the fuel neck. The hoses would be dry rotted and split and the fuel neck would have rust holes in it. If you can't get the car on a lift, you will need to jack the car up on the passenger rear area to be able to look at the eval canister for the rubber hoses.

Re: P0440

Posted: Thu Feb 08, 2018 8:42 am
by jonnymopar
I had a 0441 on my car intermittently for years. It ended up being a dry-rotted and cracked hose that I would have never found. I ended up having to bring it to the dealer to have the system smoke tested. It was a small crack in one of the hoses going to the NVLD (or Leak Detection Pump for non-NGC cars). Worse, the crack was facing up, so I saw absolutely nothing wrong from the underside of the car. So give it a real good look.

Re: P0440

Posted: Thu Feb 08, 2018 8:52 am
by occasional demons
When my purge flow valve was not connected to vacuum, the CEL/code would come on for that, every 6 months or so. But it never made any noticeable impact on how it ran, or fuel mileage. If the CEL didn't work, you wouldn't have known there was any issue at all. :dontknow: