Diagnosing code 0455

Tiny
JONSOLOW13
  • MEMBER
  • 2014 MAZDA 5
  • 2.5L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 152,000 MILES
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?
Saturday, March 7th, 2020 AT 10:17 PM

4 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
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
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Saturday, March 7th, 2020 AT 10:33 PM
Tiny
AL514
  • MECHANIC
  • 4,793 POSTS
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.
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Sunday, March 8th, 2020 AT 6:13 AM
Tiny
JONSOLOW13
  • MEMBER
  • 133 POSTS
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
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Sunday, March 8th, 2020 AT 11:09 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
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
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Sunday, March 8th, 2020 AT 8:48 PM

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