P0455

Low Severity

EVAP System Large Leak Detected

EVAP System

What Does P0455 Mean?

A significant leak in the EVAP system. Often a loose gas cap or a disconnected hose.

Common Fix

Replace gas cap or fix disconnected hose

Estimated Cost (DIY)

$5 - $50

Symptoms

  • ⚠️Check engine light
  • ⚠️Possible fuel smell
  • ⚠️Failed emissions

Related Symptoms

Check engine light on

Common Causes

Loose or missing gas caplikely
Disconnected EVAP hosepossible
Cracked canister or hosepossible
Failed purge or vent valve stuck openpossible

How to Diagnose P0455

  1. 1Check gas cap — tighten or replace
  2. 2Visual inspection of all EVAP hoses
  3. 3Smoke test EVAP system if cap is OK
  4. 4Check purge and vent valve operation

OEM Diagnostic Flowchart

Scroll to load technician if/then branches.

Read live data and freeze frame for P0455 to pinpoint the cause before buying parts.

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Related Resources

Repair guides, symptom pages, and wiring diagrams related to P0455.

OEM Manual Evidence

Browse →
2013 GMC Truck Yukon XL Denali AWD V8-6.2L A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL Denali AWD V8-6.2L Service Manual | Operation CHARM Operation CHARM : Car...

2013 GMC Truck Yukon XL Denali 2WD V8-6.2L A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL Denali 2WD V8-6.2L Service Manual | Operation CHARM Operation CHARM : Car...

2013 GMC Truck Yukon XL 4WD V8-6.0L A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL 4WD V8-6.0L Service Manual | Operation CHARM Operation CHARM : Car repair...

2013 GMC Truck Yukon XL 4WD V8-5.3L A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL 4WD V8-5.3L Service Manual | Operation CHARM Operation CHARM : Car repair...

Related Symptoms

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Check engine light onSymptom Hub

A check-engine light is a graph entry point into code pages, symptom-specific diagnosis, and the exact repair categories most often associated with those failures.

Exact Vehicle Hubs

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2013 Gmc Truck Yukon Xl 4wd V8 5.3l Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to P0455.

2013 Gmc Truck Yukon Xl 4wd V8 6.0l Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to P0455.

2013 Gmc Truck Yukon Xl Denali 2wd V8 6.2l Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to P0455.

2013 Gmc Truck Yukon Xl Denali Awd V8 6.2l Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to P0455.

Related Codes

P0440: EVAP System MalfunctionRelated

General EVAP system fault — the system that captures fuel vapors is not working properly.

P0442: EVAP System Small Leak DetectedRelated

A small leak in the EVAP system, often a deteriorated gas cap seal or a tiny crack in a hose.

P0456: EVAP System Very Small Leak DetectedRelated

A very small leak in the EVAP system — smaller than P0442.

Frequently Asked Questions

Is P0455 the gas cap code?
Most often yes. A loose, cracked, or missing gas cap is the #1 cause of P0455.
How long after tightening the cap does the code clear?
The code clears after 2-3 drive cycles (cold start, warm up, highway driving) if the leak is fixed.

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