Diagnosing code 0455

2014 MAZDA 5
152,000 MILES • 2.5L • 4 CYL • 2WD • AUTOMATIC
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JONSOLOW13
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So, the car listed above that i just bought started showing a P0455 code. We changed the gas cap- failed to cure the issue.

Can you suggest a methodology to find the leak?
Mar 7, 2020 at 10:17 PM
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JACOBANDNICKOLAS
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Hi,

The code indicates there could be a large leak. Check all EVAP related hoses. Picture 1 below shows the hose going to the purge solenoid. Make sure nothing is loose, damaged, or disconnected.

Under the vehicle near the fuel tank, there are several EVAP components. See pic 2. Check all hoses to make sure nothing was damaged.

Now, the easiest way to locate a leak is by having the EVAP system smoke tested. Basically, smoke is injected into the system and will leak out where the problem is located.

However, since this is a large leak, you should be able to find something disconnected or damaged.

Let me know if this helps or if you have other questions.

Take care,
Joe

Mar 7, 2020 at 10:33 PM
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AL514
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Just to add a little info, usually when it's a large leak like this, if no broken hoses are found, it's the venting valve back by the gas tank. These valves stick open because of where they're located being exposed to dirt and debris from the road.its a 2 wire solenoid. But he's correct about smoke testing the system if possible.
Mar 8, 2020 at 6:13 AM
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JONSOLOW13
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I will let you know what happens. Also, you were tremendous help to my 2010 Ford Focus evap problem. We ended up replacing the entire fuel pressure sensor including the "box" and harness. Problem solved!!!

You guys are amazing, is all I can say. Thanks so much!!!

Jon
Mar 8, 2020 at 11:09 AM
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JACOBANDNICKOLAS
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I remember that one. LOL I'm glad you got it fixed. AL514 has a good point. Make sure to follow through with that as well. Let us know what you find.

Take care,
Joe
Mar 8, 2020 at 8:48 PM