P0446 on 2016-2019 Chevrolet Cruze: EVAP Vent Control Circuit Causes and Fixes

What's Unique About the 2016-2019 Chevrolet CRUZE

The second-generation Chevrolet Cruze (2016-2019) with the 1.4L engine is specifically known to have a design issue that triggers the P0446 code. General Motors issued Technical Service Bulletin (TSB) #17-NA-233, which identifies the cause as water getting trapped in the EVAP canister's filter pipe. The original pipe's fresh air inlet is located in the left rear wheelhouse, where it is susceptible to water intrusion from road spray. This water can then freeze in cold climates or create a blockage, preventing the system from venting. The TSB provides a procedure to replace the pipe and relocate the vent to a more protected location.

Diagnostic Flowchart

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

Generation note: The 2016 model year was a transition year. This guide applies to the second-generation Cruze, which began in 2016. It does not apply to the 2016 "Cruze Limited," which was a continuation of the first-generation body style.

Symptoms You May Notice

• Check Engine Light is on
• Difficulty filling the fuel tank (the pump nozzle clicks off repeatedly).
• Slight decrease in fuel economy.
• A faint fuel odor.

Most Likely Causes

1. Water Trapped in EVAP Canister Filter Pipe 🔴 High Probability This is a documented design issue acknowledged by GM in TSB #17-NA-233. The original filter pipe design allows water intrusion from the rear wheelhouse, which then freezes or creates a blockage, preventing the system from venting. GM initially released a fix to add a boot to the connector (Part No. 84344135) in July 2017, but later superseded this with a full replacement and relocation of the pipe (Part No. 84593981) in November 2019.
   How to confirm: Visually inspect the EVAP canister and its filter pipe, located behind the left rear wheelhouse liner. Disconnect the pipe from the canister and check for water or ice. The TSB procedure is the definitive diagnosis and fix.
   Typical fix: Replace the original evaporative emission canister filter pipe with the redesigned part as per the instructions in TSB #17-NA-233. This involves removing the left rear wheelhouse liner, disconnecting the old pipe, and installing the new pipe, which routes the vent to a higher, more protected location, requiring a new hole to be drilled.
   Est. part cost: $50-$100
2. Failed EVAP Vent Valve / Solenoid 🟡 Medium Probability The vent valve (or solenoid) is a moving part that can fail over time by getting stuck open or closed, or by having an internal electrical fault. It is often integrated with the charcoal canister on this model.
   How to confirm: Use a capable bi-directional scan tool to command the vent valve to open and close. You should hear an audible click from the rear of the vehicle near the fuel tank. If it doesn't respond, test the wiring for power (12V with key on) and ground. If power and ground are present but the valve doesn't work, the valve itself has failed.
   Typical fix: Replace the EVAP vent valve. On the 2016-2019 Cruze, this valve is part of the charcoal canister assembly, so the entire canister must be replaced. 🎬 See this walkthrough for replacing the EVAP vent assembly
   Est. part cost: $100-$200 for a canister assembly
3. Clogged or Blocked Charcoal Canister ⚪ Low Probability Over time, or if the fuel tank is consistently overfilled ("topping off"), the charcoal pellets inside the canister can become saturated with liquid fuel or break down, causing an internal blockage that prevents venting.
   How to confirm: After confirming the vent valve and filter pipe are clear, disconnect the lines to the canister and gently try to blow through it. If there is significant resistance compared to a new part, the canister is clogged internally. A technician in a YouTube video confirmed this was the cause on a 2017 Cruze after finding the vent solenoid was working but air could not pass through the canister.
   Typical fix: Replace the charcoal canister assembly.
   Est. part cost: $100-$200
4. Damaged Wiring or Blown Fuse ⚪ Low Probability
   How to confirm: Visually inspect the wiring harness leading to the vent solenoid for any breaks, corrosion, or damage, especially near the rear wheel where it's exposed. Check the under-hood fuse box for fuses related to the emissions system (e.g., fuse #13 on some models).
   Typical fix: Repair the damaged section of wire or replace the blown fuse. If a fuse blows repeatedly, there is a short circuit that must be diagnosed.
   Est. part cost: $1-$20

Rare But Worth Checking

• Faulty EVAP Purge Valve: While the purge valve (located in the engine bay) can fail, it typically sets other codes like P0496. However, if it gets stuck open, it can sometimes contribute to EVAP system performance issues that may flag a P0446 code. This is not a primary cause for P0446.

Diagnosis Steps

1. Read the code with an OBD-II scanner to confirm P0446 is present.
2. Review GM Technical Service Bulletin #17-NA-233, as the condition it describes is the most likely cause.
3. Raise and support the vehicle safely. Locate the EVAP charcoal canister and vent filter pipe near the fuel tank, behind the left rear wheelhouse liner.
4. Remove the left rear wheelhouse liner to access the components.
5. Inspect the vent filter pipe for signs of water, ice (in cold climates), dirt, or other blockages. Disconnect it and check if it's clear.
6. If no obvious blockage is found, inspect the wiring and connector at the vent valve solenoid for damage or corrosion.
7. Using a bi-directional scan tool, command the EVAP vent solenoid to close. Listen for a distinct click. Command it to open and listen again. No click suggests a bad solenoid or a wiring issue.
🎬 Watch: How to test and replace the vent control valve
8. If the solenoid clicks, use the scan tool to monitor the Fuel Tank Pressure (FTP) sensor. With the vent open, it should read near 0 inches of H2O. Command the purge valve to activate slightly; a vacuum should build. Then, command the vent valve open; the vacuum should release instantly. A slow release indicates a blockage.
9. If the TSB procedure is performed, the new filter pipe is designed to prevent reoccurrence by relocating the air intake.

Parts You'll Likely Need

• Evaporative Emission Canister Filter Pipe (OEM #84593981) — This is the specific, redesigned part called for in the final version of TSB #17-NA-233 to fix the known water intrusion issue that causes P0446 on this vehicle. It relocates the vent inlet.
  Trusted brands: ACDelco, GM Genuine Parts
  OEM price range: $50-$100
  Aftermarket price range: $40-$80
• Vapor Canister / Charcoal Canister (OEM #84121856) — If the canister itself is clogged with charcoal debris or fuel-saturated, or the integrated vent valve has failed, the entire assembly must be replaced.
  Trusted brands: ACDelco, GM Genuine Parts
  OEM price range: $120-$200
  Aftermarket price range: $80-$150

Related Codes That Often Appear With This One

• P0451 — This code indicates a problem with the Fuel Tank Pressure Sensor's performance. A blockage in the vent system (causing P0446) can prevent the tank pressure from changing as expected during EVAP tests, which can trigger a P0451 code. A diagnostic video on a 2017 Cruze showed both codes present, which were ultimately resolved by replacing a clogged charcoal canister.
🎬 Watch: Diagnosing P0446 and P0451 on a 2017 Cruze

Technical Service Bulletins (TSBs) & Recalls

• 17-NA-233: Malfunction Indicator Lamp (MIL) Illuminated - DTC P0446 Set. This bulletin, last updated in November 2019, provides the specific procedure to replace the EVAP canister filter pipe due to water intrusion. It involves drilling a new mounting hole to relocate the vent.
• PIE0455: An information bulletin from March 2018 requesting field data from technicians on vehicles that have set a P0446 code, indicating GM was actively investigating the root cause of this issue before issuing the final TSB fix.

Platform-Specific Known Issues

• TSB #17-NA-233: GM identified that the Malfunction Indicator Lamp can illuminate with DTC P0446 because of water trapped in the evaporative emission canister filter pipe. The fix involves removing the left rear wheelhouse liner and replacing the pipe with a newly designed part that relocates the air inlet to a less exposed area. The labor time for this specific bulletin is listed as 0.6 hours.