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P0455 Buick Code - Evaporative Emission System Large Leak Detected

- Code Popularity: 60,634 Views
- Repair Importance Level: 1/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC P0455 Buick?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • 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
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How to Fix the DTC P0455 Buick?

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

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)

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0455 Buick code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)
  • A noticeable fuel odor may result from fuel vapor release

Code P0455 Buick 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 Buick - Evaporative Emission System Large Leak Detected - AutoCodes.com
P0455 Buick Code - Evaporative Emission System Large Leak Detected

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