AutoCodes – GMC – P0455 2016 GMC Sierra

P0455 2016 GMC Sierra Code - Evaporative Emission System Large Leak Detected

Quick Answer

The Engine Control Module (ECM) tests the Evaporative Emission (EVAP) system for a large leak or restrictions to the purge path in the EVAP system. Common causes include Missing or loose fuel cap, Incorrect fuel filler cap used, Fuel filler cap remains open or fails to close. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

What it means: P0455 2016 GMC Sierra indicates Evaporative Emission System Large Leak Detected.
Common causes: Common causes include Missing or loose fuel cap, Incorrect fuel filler cap used, Fuel filler cap remains open or fails to close.
Severity: Low - monitor the vehicle and repair when practical.
Can I drive?: The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.

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Code Popularity 406

How popular is this code, among other codes? Low

Repair Importance Level

Low (Monitor) (1 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 31, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P0455 2016 GMC Sierra Description

The Engine Control Module (ECM) tests the Evaporative Emission (EVAP) system for a large leak or restrictions to the purge path in the EVAP system. When the enabling criteria has been met, the ECM commands the EVAP vent solenoid valve and purges the solenoid valve ON, allowing vacuum into the EVAP system. The ECM monitors the fuel tank pressure sensor voltage to verify that the system is able to reach a calibrated level of vacuum before a calibrated amount of purge volume has passed through the system. The Diagnostic Trouble Code (DTC) will be set when the EVAP system is not able to achieve or maintain a calibrated level of vacuum less than -2.74 kPa (-11 in H20) before a calibrated amount of purge volume has passed through the system.

OBDII Code P0455 2016 GMC Sierra - Evaporative Emission System Large Leak Detected - AutoCodes.com — P0455 2016 GMC Sierra Code - Evaporative Emission System Large Leak Detected

What does this mean?

What are the Possible Causes of the DTC P0455 2016 GMC Sierra?

Missing or loose fuel cap
Incorrect fuel filler cap used
Fuel filler cap remains open or fails to close
Foreign matter caught in fuel filler cap
Leaking EVAP Canister
Leaking EVAP System Hose
Leaking Fuel Tank
Faulty Fuel Tank Pressure Sensor

How to Fix the DTC P0455 2016 GMC Sierra?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

The P0455 code means that the control module has detected a small leak in the Evaporative Emission (EVAP). A loose fuel tank filler cap is the most common cause that will trigger the P0455 code.

There is a factory service bulletin for all the models from 2000 through 2021. The factory states that there are seven critical connections that could likely lead to this DTC being set:
1. Purge tube to purge valve (at intake manifold)
2. Purge tube to chassis EVAP line (at the rear of the engine, near transmission)
3. Chassis EVAP line to canister (at canister)
4. Fuel tank load line to canister (at canister)
5. Vent valve line to vent valve (at vent valve)
6. Fuel tank load line jumper connection (near fuel tank)
7. Fuel tank cap is closed properly (at refuel compartment)

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0455 2016 GMC Sierra code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0455 2016 GMC Sierra code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.