P0455 on 2013-2020 Chevrolet Trax: EVAP Large Leak Causes and Fixes

What's Unique About the 2013-2020 Chevrolet TRAX

The Chevrolet Trax, particularly with the 1.4L engine, is known for a few specific EVAP system weaknesses. The most notable is a documented issue where spiders can build nests inside the EVAP canister, causing a blockage or leak that triggers a P0455 code. This was significant enough for GM to issue a Technical Service Bulletin (TSB #17-NA-383). Additionally, the EVAP purge valve is a very common failure point on this platform, often getting stuck open or closed and sometimes leading to extended warranty coverage from GM, such as Special Coverage Program N232395300 for 2020 models.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light is on
• A faint smell of fuel, particularly around the rear of the vehicle or when parked in a garage.
• Difficulty starting immediately after refueling (if the purge valve is stuck open, flooding the engine with vapors).
• Rough idle or stalling at low speeds (if the purge valve is stuck open, creating a vacuum leak).
• Gas pump nozzle clicks off repeatedly when trying to refuel (if the EVAP canister or vent is blocked).

Most Likely Causes

1. Loose or Faulty Gas Cap 🔴 High Probability This is the most common cause for a P0455 code on any vehicle, as the cap seal can degrade over time or may not have been tightened correctly after refueling. It's always the first and cheapest thing to check.
   How to confirm: Ensure the gas cap is tightened until it clicks at least three times. Inspect the rubber seal on the cap for cracks, stiffness, or damage. Check the fuel filler neck for rust or debris that could prevent a good seal.
   Typical fix: Tighten the cap. If the seal is damaged or the cap is old, replace it with a new one. Using a genuine OEM cap is often recommended as some aftermarket caps may not seal properly.
   Est. part cost: $15-$30
2. Faulty EVAP Purge Valve/Solenoid 🔴 High Probability The purge valve on the 1.4L engine is a very common failure item, often getting stuck open or closed. 🎬 Watch this troubleshooting guide for a Trax with P0496. This issue is so prevalent that GM has issued special coverage program N232395300, extending the warranty for this part on 2020 Trax models to 15 years or 150,000 miles.
   How to confirm: Remove the valve (located on top of the engine) and try to blow through it. If air passes through, the valve is stuck open and is faulty. A stuck-open valve often triggers code P0496 as well. A stuck-closed valve can also cause P0455 because no vacuum is drawn during the system test, which the ECU interprets as a large leak.
   Typical fix: Replace the purge valve. It is an easy DIY job, typically taking less than 15 minutes with no special tools required.
   Est. part cost: $30-$60
3. Damaged EVAP Canister (Spider Nests) 🟡 Medium Probability As documented in TSB #17-NA-383, spiders have been known to lay nests within the fresh air inlet port of the EVAP canister on the Trax, Sonic, and Encore, causing a restriction that sets a P0455 or P0446 code.
   How to confirm: Visual inspection of the canister and its vent port for webs or blockages is the first step. A smoke test is the definitive way to confirm a leak from the canister body itself.
   Typical fix: Replacement of the EVAP canister assembly. The TSB procedure is to inspect and, if a restriction is found, replace the canister.
   Est. part cost: $100-$200
4. Cracked or Disconnected EVAP Hoses 🟡 Medium Probability Rubber and plastic hoses become brittle over time due to heat and age, leading to cracks. Connections can also become loose, especially the push-connect fittings used throughout the system.
   How to confirm: Visually inspect all accessible EVAP lines between the engine bay, charcoal canister, and fuel tank. A smoke test is the most effective method to find a hard-to-see crack or a poorly seated connection.
   Typical fix: Replace the damaged section of hose or reconnect a loose line.
   Est. part cost: $10-$50
5. Faulty EVAP Vent Solenoid ⚪ Low Probability The vent solenoid, typically located near the EVAP canister, can fail and get stuck open, creating a large leak condition. It is exposed to road debris and moisture under the car, which can lead to failure.
   How to confirm: Requires testing with a capable scan tool to command the valve closed and see if it holds a vacuum or smoke, or by applying 12v directly to the solenoid to check its operation.
   Typical fix: Replace the vent solenoid. This is sometimes sold separately from the canister.
   Est. part cost: $40-$80

Rare But Worth Checking

• Cracked Fuel Filler Neck: Rust or physical damage can cause the metal filler neck (where you insert the gas nozzle) to crack, creating a leak that is often hard to spot without a smoke test.
• Faulty Fuel Tank Pressure Sensor: While uncommon, the sensor that monitors EVAP system pressure can fail, providing incorrect readings to the computer. This usually triggers other specific sensor-related codes but can sometimes contribute to a P0455 diagnosis.

Diagnosis Steps

1. Check the gas cap. Remove it, inspect the seal for damage, and reinstall it, ensuring it clicks several times. Clear the code and drive for a few days to see if it returns.
2. Visually inspect the EVAP Purge Valve on top of the engine. It's easily accessible. Check for any obvious cracks in the valve body or its connecting hoses.
3. Test the Purge Valve. Disconnect the valve and attempt to blow through it. If air passes, it's defective and needs replacement. If no air passes, it could be stuck closed; a scan tool can command it open to verify function.
4. Perform a visual inspection of all visible EVAP hoses and the charcoal canister (located near the fuel tank) for obvious cracks, damage, or loose connections.
5. Inspect the EVAP canister vent port for spider webs or other blockages as described in TSB #17-NA-383.
6. If the cause is still not found, the next step is a professional smoke test. A machine injects non-toxic smoke into the EVAP system, and any leaks will be made visible by the escaping smoke. This is the most reliable way to find cracked hoses, a faulty canister, or a leaking fuel filler neck.

Parts You'll Likely Need

• Vapor Canister Purge Valve (OEM #55567453 (Superseded by ACDelco 214-2317)) — This is a very frequent failure point on the 1.4L engine in the Trax, often getting stuck open or closed.
  Trusted brands: ACDelco, Dorman, Standard Motor Products
  OEM price range: $40-$60
  Aftermarket price range: $25-$50
• Fuel Cap (OEM #GT330 (ACDelco)) — A worn out or improperly tightened gas cap is the simplest and a very common cause for a large EVAP leak code.
  Trusted brands: ACDelco, Stant
  OEM price range: $20-$30
  Aftermarket price range: $15-$25
• EVAP Vapor Canister (OEM #42782039) — Can become cracked or, specific to the Trax, can become blocked by spider nests as noted in TSB #17-NA-383.
  Trusted brands: ACDelco, Duralast
  OEM price range: $150-$220
  Aftermarket price range: $100-$180
• EVAP Vent Solenoid / Valve (OEM #84524035 (ACDelco)) — Located near the canister, this valve can get stuck open due to dirt and moisture, causing a large leak.
  Trusted brands: ACDelco, Dorman, Standard Motor Products
  OEM price range: $20-$45
  Aftermarket price range: $15-$35

Related Codes That Often Appear With This One

• P0442 — This code indicates a small EVAP leak. It can appear alongside P0455 if the system detects leaks of varying sizes during different tests, or as a precursor to the larger leak.
• P0496 — This code means 'EVAP Flow During a Non-Purge Condition' and is very commonly caused by a purge valve that is stuck open. If you see P0496 with P0455, the purge valve is the prime suspect.
• P0171 — This code indicates 'System Too Lean (Bank 1)'. It can be triggered if the purge valve is stuck open, creating a vacuum leak that allows unmetered air into the intake manifold, disrupting the air-fuel ratio.

Technical Service Bulletins (TSBs) & Recalls

• 21-NA-124: Diagnostic tips for EVAP leaks causing P0442 and/or P0455.
• 17-NA-383: Procedure to replace the EVAP canister due to spider nests causing P0455 or P0446.
• N232395300: Special Coverage extending the warranty on the EVAP purge valve for certain 2020 models.

Platform-Specific Known Issues

• TSB #17-NA-383: Spiders have been found to build nests in the EVAP canister vent port, causing a restriction that triggers P0455 or P0446. The official fix is to inspect and replace the canister if a blockage is found.
• TSB #21-NA-124: This bulletin provides dealers with advanced diagnostic tips for finding EVAP leaks related to codes P0442 and P0455.
• Special Coverage Program N232395300: For 2020 Trax models (and other GM vehicles), the warranty on the EVAP purge valve is extended to 15 years or 150,000 miles due to a high failure rate where the valve sticks open.

Mechanic-Grade Diagnostic Values

• EVAP Purge or Vent Solenoid Coil Resistance — expected: 15 to 30 Ohms. Failure: A reading of infinity (OL) indicates an open coil, while a reading of zero indicates a short. Either requires replacement.
• EVAP Vent Solenoid Control Wire Voltage (Key On, Engine Off, Commanded Off) — expected: ~12 Volts (Battery Voltage). Failure: A reading of 0 volts suggests an open in the circuit (e.g., broken wire, bad fuse, or open solenoid coil), which can trigger a 'circuit low' fault code like P0449.

Scan Tool Commands That Help

• GDS2 / Professional Scan Tool: EVAP System Service Bay Test — This is a comprehensive, automated test the dealer uses. It commands the vent and purge valves to seal the system, monitors the fuel tank pressure sensor, and reports if the system can hold a vacuum. It's the first step in software-based diagnosis after checking for codes.
• GDS2 / Bidirectional Scan Tool: Output Controls -> EVAP Vent Solenoid Command — This command allows a technician to manually open and close the vent solenoid. It is used to verify if the solenoid clicks and operates correctly and to seal the system for a smoke test.
• GDS2 / Bidirectional Scan Tool: Output Controls -> EVAP Purge Solenoid Command — This command manually pulses the purge solenoid. It's used to check if the solenoid is stuck or responding to the computer's command. A technician can feel for clicking or check for vacuum flow while commanding it open.

Wiring & Ground Locations

• Engine Block Ground — A primary ground strap typically connects from the engine block or cylinder head to the chassis or directly to the negative battery terminal. On similar GM vehicles, a critical PCM ground is located on top of the engine block.. A poor engine ground can cause erratic behavior in all sensors and solenoids controlled by the Engine Control Module (ECM), including the EVAP purge and vent valves. This can lead to incorrect operation and false codes.
• Chassis/Frame Ground — Look for ground wires bolted to the frame rail, particularly near the fuel tank and under the driver's side of the vehicle.. The EVAP vent solenoid and fuel tank pressure sensor are located near the fuel tank. A corroded or loose ground in this area can directly cause a malfunction of these components, leading to EVAP codes.
• Battery to Chassis Ground — A main ground cable runs from the negative battery terminal to a point on the vehicle's chassis/frame, often near the radiator support or strut tower.. This is the primary ground for the entire vehicle's electrical system. Corrosion here can cause widespread, unpredictable electrical issues.

"I Checked Everything" — The Actual Cause

• A stuck-closed EVAP purge valve. A smoke test will show no leaks because the system is sealed, but the code sets because the ECM cannot draw the required vacuum through the valve during the test cycle.
• A faulty Fuel Tank Pressure (FTP) sensor. The system may be perfectly sealed, but if the FTP sensor provides an incorrect reading to the ECM, the computer may interpret it as a large leak.
• An intermittent electrical issue in a valve's control circuit. A smoke test only checks for physical leaks, but a broken wire or faulty driver in the ECM could prevent a valve from closing properly during the self-test, causing the code to set without an actual physical leak being present.

OEM Part Supersession History

• 55567453 (Purge Valve) → 28289971 or ACDelco 214-2317 — Standard part revision and improvement. The high failure rate of this valve led to multiple updates.
• 95128163 (EVAP Canister) → 42782039, which was then superseded by 42933886 — Part design updates, potentially to address issues like the spider nest problem (TSB #17-NA-383).
  Heads up: When replacing the canister, it is critical to use the latest part number specified for the vehicle's VIN to ensure compatibility with hoses and electrical connections.

Model Year Variations Within This Range

• 2020: The 2020 Chevrolet Trax with the 1.4L engine is specifically included in GM's Special Coverage Program N232395300, which extends the warranty on the EVAP purge valve to 15 years or 150,000 miles. Owners of these vehicles may be eligible for a free replacement at a dealer.