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Discussion Starter #1
My CEL just came on yesterday. 2010 Santa Fe 3.5 L V6, 140K kms.

Torque Pro tells me it is P0456 (very small evap leak). It is further indicated that MID$3c TID$82 EVAP monitor (0.040") is not OK. Min 0 Pa/s, max 9.25 Pa/s, actual reading is 21 Pa/s. Anyone know what all this means?

I've had no work done on the fuel/evap system (fuel sending unit, etc. untouched), I don't top off the tank, and I don't smell any fuel, so I don't think this is related to crud in the o-rings as others have found, unless this can just happen with time, in the absence of any repair work. I last filled the gas tank 4 days ago.

Is this likely as simple as replacing the fuel cap?
 

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Check the gas cap and look at the metal collar. If there is rust it will allow a small leak. Clean off the rust (not in the hole, a small rag may help stuff in) clean the edge towards the outside of the collar so it doesn't go in the tank. Film of oil or such to keep if from rusting may help as well. Cheap metal or not properly coated with paint don't stand up in the rust belt.
 

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Discussion Starter #3
Thanks for the quick reply Tripplec.

Just looked, and there is a small amount of rust on the fuel filler tube (not sure this is the proper term) where the gas cap gasket makes contact. Would some fine grit sandpaper be the best bet to remove it?

Here's a picture:
 

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Yes, buff that with some fine sandpaper, being careful like trip said not to get debris in the tank. If you do, clean it as well as possible with a rag.

After many years using silicone grease in many places around cars, fighter aircraft, and other hardware, I'd say put some on the filler lip where the gasket mates and on both sides of the gasket. Some rubber is sensitive to deterioration if it's lubricated with petroleum based grease but silicone grease won't harm it.

.
 

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Yeah the Hornet got you on track. You'll likely find it clear. Not unique to SF's just learned this in the School of Hard Knock. Still waiting to graduate but new stuff keeps in learning...the hard way.
 

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Bribe a Hyundai tech with a coupon for meal at food joint to walk out with tablet and perform an EVAP self test to verify repair attempt..
 

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Discussion Starter #8
No codes yet, although I haven't driven it much since cleaning things up.

I'll take it for a run down the highway tomorrow and see what happens. Need to make sure all monitors are ready since I need to get it e-tested before the end of the month.
 

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When one clears the DTC codes, it also clears the readiness monitors.
So whenever it tests the monitors and complete the cycles is when you will know if it worked or not.
I have a P0440. Checked the vent valve and cleared the codes.
I didn't have a CEL for three weeks. But, I checked the readiness monitors and four of them were incomplete
They didn't check/complete for over 300 miles. When it did, the CEL came back on.
I am going to have to get it tested with a smoke machine.
 

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I know disconnecting the battery kills all the Drive clean status from Ready state. It can take a long time to reset them back to READY status with driving. Some with never set in the winter due to the cold. Those who have a winter birthday like me must be aware if doing any repairs not to disconnect the battery. I never used to in my younger days but just started with some modern vehicles as everyone else seems to.

I did not think clearing a code would as my code reader can delete codes but only the select one if there are more than one I have to select the other after and so on. Hmm Never the less knowing that would make me cautious in the winter if I needed to have it for a test (every two years here).

For that code I would have left it active since it don't take too long for it to clear if fixed. But that rust in the photo would definitely do it.
 

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Discussion Starter #11
CEL came back on today. Same code as before P0456.

All I've done to trouble shoot this is clean up the gas filler tube where the gas cap gasket seals against it. Should I try replacing the gas cap, or just take it in for a diagnostic?
 

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Discussion Starter #12
I also wonder if it could be a leaking purge valve. Any thoughts on this?

If this is a possibility, does anyone have a picture of what the purge valve looks like, and where it is located on the 3.5 L V6? If it is accessible, I could pull it off and check it out.
 

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I also wonder if it could be a leaking purge valve. Any thoughts on this?

If this is a possibility, does anyone have a picture of what the purge valve looks like, and where it is located on the 3.5 L V6? If it is accessible, I could pull it off and check it out.
On bracket adjacent to throttle body,, solenoid looking thing, line to intake close to throttle body, with line going off that look like fuel line to solenoid..
 

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Discussion Starter #14
Yesterday I bought a new OEM gas cap from my local Hyundai dealership. Will have to drive a bit more to see if the code comes back.

Just for fun, I pulled out the back seat and took a look at the top of the gas tank through the access hatches. When I opened up the one behind the driver's seat, I could faintly smell gas (the tank is over 3/4 full at the moment), and it looks like there has been a leak - indicated by a stain around the lock ring. On the passenger side, there was no smell of fuel, and no visual indication of a leak.

I'm the original owner of this Santa Fe, and it has never had the fuel system worked on. Is it possible that the gasket on the driver's side has failed due to age and accumulation of grit, and replacing it will solve the P0456 issue?

Picture attached of what I saw on the driver's side.
 

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IMO you should not clear the codes for this issue. Just wait for a few rides and if ok it will clear itself a lot faster then waiting for a reocurrence!!

If the ready state is also affect as mention (it is another reason to not clear these codes) Getting the entire engine status back to ready takes a long time!!

Forum not working properly posts not being submitted. I had to reload and do it again a second time.
 

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Yesterday I bought a new OEM gas cap from my local Hyundai dealership. Will have to drive a bit more to see if the code comes back.

Just for fun, I pulled out the back seat and took a look at the top of the gas tank through the access hatches. When I opened up the one behind the driver's seat, I could faintly smell gas (the tank is over 3/4 full at the moment), and it looks like there has been a leak - indicated by a stain around the lock ring. On the passenger side, there was no smell of fuel, and no visual indication of a leak.

I'm the original owner of this Santa Fe, and it has never had the fuel system worked on. Is it possible that the gasket on the driver's side has failed due to age and accumulation of grit, and replacing it will solve the P0456 issue?

Picture attached of what I saw on the driver's side.

I am more of the replace the rotted - falling apart lock ring and the green ring (packing) around top of tank.. you have signs of fuel leakage, so that very well says we have EVAP leak during test of system...

Wanna have some fun,, get to where assistant can blow into tank via vent hose,, and while trying to hold a couple psi (2-3) in the tank,, you use spray bottle full of soapy water mix and spray the top of module there,,, see if it make bubbles...
 

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Spoke with a mechanic today about the evap leak
He said that it could be the gas tank
And that removing the back seat might show where it is leaking
Hmm, it sounds like there is a lot of work to do to test this assumption

Looks like someone is way ahead of me
 

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Its been quite a while since I have seen gas tanks rusting out. Many are now a plastic tank as well in a number of vehicles I have had. EG the Caravan back in 97 for one.
 

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Discussion Starter #19
I've boooked an appointment to have the lock ring and gasket replaced next week. I'll report back with the results.
 

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Discussion Starter #20
Had the lock ring and gasket replaced on the driver's side. Today the CEL came back on. This time it's showing P0442 (small evap leak), so my leak has gone from very small to small - Yay!

Is it possible that the shop just did a bad job replacing the gasket?

I'm going to test the purge valve to see if it is leaking. Other than that, I think my best option is to take it in to the dealership for a leak test.

Just to add to the fun, my plates expire tomorrow, and I'm pretty sure that this error code will be an automatic fail for the e-test.
 
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