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Discussion Starter · #1 ·
Just hit 10,000 miles and started up and check engine (mil) light came on. I got her home and put her on the computer and got the PO456 Evaporative emission system leak detected (very small leak)

so very small sounds like very HARD to find. Taking her to the dealer tomorrow. Also I assume MDS deactivates when MIL is on. I noticed no econ light on the way home.

Thanks again... will post follow up

this has me worried..
 

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2009 Challenger R/T Auto
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Bets are that this is a loose or leaking gas cap. It's usually the culprit. I had it start after putting on a cheap Autozone locking cap. Changed it out with the Stant and have not had a problem since.
 

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Causes

Usually this P0456 code is caused by an incorrect or faulty gas cap. Filling the fuel tank with the engine running could conceivable cause this code as well or if the cap wasn't properly tightened. Any of the following could also be the cause:

  • A small leak in any of the EVAP hoses or fuel tank hoses
  • A small leak in the purge valve or vent valve
  • The EVAP Canister may be leaking
Possible Solutions

First, using a scan tool activate the vent solenoid, sealing the system. Then monitor the fuel tank pressure (FTP) sensor. If the system is sealing properly, the number will stay consistent. If is isn't, the pressure sensor will show that as well. If the system slowly leaks, use a smoke machine and watch for smoke exiting the system at any EVAP component. Any where there is smoke exiting the system, that is the faulty component. Do not pressurize the EVAP system with air pressure. Doing so can damage the purge and vent solenoids in the system.
 

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New member log time reader,
2012 pro charged srt8 challenger.
Runs like a dream with scary power but now I’m stuck with very small evap leak with check gas cap where mileage is.

replaced capx2 ,purge valve, LDP, and both fuel pumps‘all recently. Wondering if a fuel pump has the leak, I do smell gas very intermittent.
At all loss, smoke test really work?

any info be greatly appreciated

thanks guys,
Michael
 

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2016 Dodge Challenger R/T Plus in Granite Crystal Metallic
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2,071 Posts
New member log time reader,
2012 pro charged srt8 challenger.
Runs like a dream with scary power but now I’m stuck with very small evap leak with check gas cap where mileage is.

replaced capx2 ,purge valve, LDP, and both fuel pumps‘all recently. Wondering if a fuel pump has the leak, I do smell gas very intermittent.
At all loss, smoke test really work?

any info be greatly appreciated

thanks guys,
Michael
Yes. Smoke test is the way to go. Had a similar issue with my Ram. Took a few times to locate the pinhole in the evap line. No issues since the $5 hose was replaced.
 
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