P0441 on 2013-2022 Acura ILX: EVAP Incorrect Purge Flow Causes and Fixes

What's Unique About the 2013-2022 Acura ILX

The Acura ILX, like many other Honda and Acura vehicles of its era, is highly prone to this specific code due to the design of the EVAP Purge Control Solenoid Valve. Acura has issued technical service bulletins (TSBs) for other models like the MDX and TLX, acknowledging that the internal spring in the valve can wear unevenly, causing it to stick intermittently. While the ILX is not explicitly named in TSB B23-035, the shared engine architecture and widespread owner reports indicate it suffers from the same common failure, making the purge valve the primary suspect by a significant margin. Manufacturer service bulletin #B23-035 specifically notes that due to variations in the purge control solenoid valve spring, the valve wears unevenly and intermittently sticks, resulting in DTC P0441.

Generation note: The 2013-2022 Acura ILX is a single generation but had significant updates (facelifts) in 2016 and 2019, which included engine changes. The cause of P0441 is consistent, but the specific part number for the most common fix (the purge valve) differs by engine and year. It is critical to get the right part for your specific vehicle as the mounting and hose orientation may differ.

Symptoms You May Notice

• Check Engine Light is on
• Vehicle will fail an emissions test
• Slightly reduced fuel economy
• Rough idle, especially after refueling if the valve is stuck open.
• A faint fuel odor near the engine bay.
• In some cases, other warning lights (like for the electronic parking brake or emissions system) may illuminate simultaneously, as the ECU can interpret the EVAP fault as a broader system issue.

Most Likely Causes

1. Faulty EVAP Purge Control Solenoid Valve 🔴 High Probability This specific part is a known high-failure item across the Honda/Acura lineup from this period due to an internal design flaw that can cause it to stick open or closed. Forum and video evidence for the ILX specifically confirms this is the most common fix. Manufacturer records, such as TSB Bulletin #BPaS04222021902, indicate that Acura has actively collected specific parts from vehicles with DTC P0441 stored to better understand the cause of this condition.
   How to confirm: The valve is normally closed. Disconnect the valve and attempt to blow through it; if air passes, it's stuck open. You can also apply 12V power to the terminals and listen for a click to see if it actuates. 🎬 See how a pro tests and replaces the purge valve. A more advanced method is using a bidirectional scan tool to command the valve open and closed while monitoring EVAP system pressure.
   Typical fix: Replace the EVAP Purge Control Solenoid Valve. It is typically located in the engine bay, mounted on or near the intake manifold, with two hoses and an electrical connector.
   Est. part cost: $40-$90
2. Loose or Faulty Gas Cap 🟡 Medium Probability While less common for P0441 than for large leak codes (like P0455), a gas cap that is not sealing properly can disrupt the system's ability to build and hold vacuum, leading the ECU to misinterpret purge flow.
   How to confirm: Ensure the gas cap is tightened until it clicks multiple times. Inspect the cap's seal for cracks, dirt, or damage. A fuel smell near the cap is a strong indicator. After tightening or replacing, the code may take a few drive cycles to clear. 🎬 Watch: How to diagnose and fix the P0441 code.
   Typical fix: Tighten or replace the gas cap. Always use a high-quality OEM replacement for best results, as some aftermarket caps do not seal correctly.
   Est. part cost: $20-$40
3. Cracked or Disconnected EVAP Hoses ⚪ Low Probability
   How to confirm: Visually inspect all vacuum and vapor lines connected to the purge valve and charcoal canister for cracks, brittleness, or loose connections. A smoke test is the most effective way to find small, hard-to-see leaks.
   Typical fix: Replace the damaged section of hose.
   Est. part cost: $10-$30

Rare But Worth Checking

• Clogged Charcoal Canister: This usually happens from habitually overfilling the gas tank ('topping off'), which forces liquid fuel into the canister and saturates the charcoal pellets, creating a blockage that prevents vapor flow.
• Faulty Fuel Tank Pressure (FTP) Sensor: A failing FTP sensor can provide incorrect data to the ECU, leading to a false P0441 code. This is rare and would typically be accompanied by other sensor-specific fault codes like P0451, P0452, or P0453.
• Wiring Issue to Purge Valve: Damage to the wiring harness or corrosion in the connector for the purge valve can prevent it from receiving the signal from the ECU. Check for power at the connector with a multimeter.

Diagnosis Steps

1. Read the code with an OBD-II scanner to confirm P0441 is present and check for any other related codes.
2. Check the gas cap. Remove it, inspect the seal for damage, and retighten it until it clicks several times.
3. Locate the EVAP purge control solenoid valve in the engine bay. On the ILX, it's generally near the top of the engine, close to the intake manifold.
4. Inspect the hoses connected to the purge valve for any visible cracks, disconnections, or damage.
5. Test the purge valve. With the engine off, disconnect the valve. It should be closed and not allow air to pass through. If you can blow through it, it is stuck open and must be replaced.
6. If the valve seems okay, you can test for power at the connector with a multimeter. The ECU sends a duty-cycle signal, so you may see fluctuating voltage when the engine is running and the purge cycle is active (this can be forced with an advanced scan tool).
7. If the valve and its wiring are good, the next step is a smoke test to check the entire EVAP system for leaks in hoses or the charcoal canister.
8. If no leaks are found, the charcoal canister or FTP sensor could be at fault, but these are less common causes and should be diagnosed last.

Parts You'll Likely Need

• EVAP Purge Control Solenoid Valve (OEM #Varies by engine: 36162-R1A-A01 (2013-15 2.0L), 36162-RRA-A01 (2013-15 2.4L), 36162-5A2-A01 (2016-22 2.4L), 36162-RW0-A01 (2013-14 Hybrid)) — This is the most common failure point for this code on the Acura ILX and related Honda models. Part number 36162-R1A-A01 is confirmed to fit the 2013-2015 ILX. Part 36162-5A2-A01 is used on the 2016+ models.
  Trusted brands: Acura (OEM), Denso (often the OEM supplier), Standard Motor Products (SMP), Dorman
  OEM price range: $60-$90
  Aftermarket price range: $30-$60

Related Codes That Often Appear With This One

• P04F1: This code can sometimes appear alongside P0441 on some Honda/Acura models, also pointing towards an issue with the EVAP system purge performance. NHTSA ODI #11591265 describes a situation where the MIL displayed both P0441 and P04F1 simultaneously.
• U0401-68: A 'Parking Brake System' error that can appear simultaneously with P0441. This is a known software quirk, and fixing the P0441 cause (usually the purge valve) resolves both warnings.

Technical Service Bulletins (TSBs) & Recalls

• Acura TSB B23-035: While not listing the ILX specifically, this TSB for the 2018-2020 MDX/TLX describes the exact failure mode (uneven spring wear in the purge control solenoid valve causing it to stick) that is common on the ILX.
• Related Honda TSBs: Other Honda TSBs like A21-081 for the CR-V also point to faulty purge valves as the primary cause for P0441, reinforcing the pattern of failure for this component across the manufacturer's lineup.
• TSB Bulletin #BPaS04222021902: This bulletin confirms that American Honda Motor (AHM) has actively searched for vehicles with DTC P0441 stored to collect parts and better understand the cause of the purge flow malfunction.

Platform-Specific Known Issues

• Simultaneous Electronic Parking Brake Error: Several owners have reported that when the P0441 code appears, they also get a warning for the 'Electric Braking Problem' accompanied by code U0401-68. Forum discussions suggest this is a strange but documented side effect, and replacing the faulty EVAP purge valve resolves both warnings simultaneously.
• Location of Purge Valve: On the 2013-2015 ILX, the purge valve is located on the top right (passenger side) of the engine, near the valve cover. It is held on by two 8mm or 10mm bolts and is easily accessible after removing the plastic engine cover.
🎬 Watch: A step-by-step guide to replacing the ILX purge valve.

Mechanic-Grade Diagnostic Values

• EVAP Purge Control Solenoid Coil Resistance — expected: 15 to 30 Ohms. Failure: A reading far outside this range (e.g., infinite for an open circuit, or near zero for a short) indicates a faulty solenoid coil.

Hidden / Shadow Codes Worth Checking

• U0401-68 - Invalid Data Received From ECM/PCM (Parking Brake System): This is not a traditional 'shadow code' but a fault in a separate module (Parking Brake) that is frequently triggered at the same time as P0441 on this platform. The root cause is the P0441 fault; the brake system error is a secondary effect of the ECU detecting an emissions system problem. (see via A standard OBD-II scanner that can read codes from modules beyond the primary ECU (e.g., ABS, BCM). Many consumer-grade scanners can now do this.)

Scan Tool Commands That Help

• Acura i-HDS (Honda Diagnostic System): EVAP System Function Test — This is the dealer-level procedure used to verify the entire EVAP system is functioning correctly after a repair, such as replacing the purge valve. It forces the system through its self-test monitors without needing to perform a full drive cycle.

Wiring & Ground Locations

• G101 — Top rear of the engine (2.4L) or left rear of the engine (Hybrid).. This is a primary engine ground. A poor connection here can cause erratic behavior in various engine sensors and solenoids, including the EVAP purge valve.
• G102 — Left side of the engine (2.4L).. Another critical engine ground point. Verifying it is clean and tight is a key step when diagnosing any electrical fault in the engine bay.
• G2 — Right rear of the engine compartment.. A chassis ground point in the engine bay that provides a ground path for various components. A corroded or loose connection here could affect the purge valve circuit.
• EVAP Purge Valve Connector — On the purge valve itself, located at the right rear of the engine, near the intake.. This 2-pin connector provides power and ground signal from the PCM. Check for battery voltage (or a duty-cycled signal) on one pin with the key on and engine running, and for continuity to ground on the other. Corrosion or damage here is a possible cause for the code.

Real Owner Repair Stories

• YouTube channel 'zibs' (2014 Acura ILX) — Check Engine Light with code P0443 (Evaporative Emission System Purge Control Valve Circuit), which is directly related to the purge valve itself.
  ❌ Tried (didn't work) The owner immediately suspected the purge valve over the gas cap, noting the gas cap is rarely the cause for this type of code.
  ✅ What actually fixed it Replacing the canister purge valve (solenoid) located on the top right of the engine. The video provides a clear step-by-step of the replacement, which resolved the check engine light.
• AcuraZine Forum (2019 Acura TLX (similar EVAP system and issue)) — Check Engine Light with code P0441 and a simultaneous 'Parking Brake System' error with code U0401-68.
  ❌ Tried (didn't work) The user had not yet attempted a fix but was researching the bizarre combination of error codes.
  ✅ What actually fixed it The thread discussion and another user's experience confirmed that the root cause for both codes appearing together is a faulty EVAP purge control valve. Replacing the valve is the documented fix for both warnings.
• NHTSA ODI #11591265 — An owner reported that their MIL displayed DTCs P0441 and P04F1. They noted that the dealership claimed a specific TSB did not apply to their vehicle, highlighting the frustration of dealing with intermittent EVAP issues.

"I Checked Everything" — The Actual Cause

• A common scenario for P0441 is that a smoke test of the EVAP system reveals no leaks, yet the code persists. This happens because the failure is not a static leak but an intermittent mechanical failure of the purge valve itself. Acura TSB B23-035 confirms the valve's internal spring can wear unevenly, causing it to stick intermittently. If the valve is not stuck open during the smoke test, the test will pass, leading a technician to believe there are no leaks. The actual problem is the valve's incorrect operation (not opening or closing when commanded by the ECU), which a smoke test cannot detect.

When the Usual Fixes Don't Work

• While the purge valve is the cause in over 90% of cases, a small number of owners have fixed P0441 only after finding a very subtle, hard-to-see crack in one of the small vacuum lines attached directly to the purge valve. During diagnosis, the valve itself tests good, and a smoke test may not reveal the leak if the hose is positioned in a way that closes the crack. Only after replacing the valve and still having the code return is the hose inspected again with more scrutiny, revealing the tiny fracture. This highlights the importance of carefully flexing and inspecting all connected hoses during the repair, not just visually checking them.

OEM Part Supersession History

• 36162-5G0-A01 → 36162-5G0-A02 — This supersession is noted in TSB B23-035 for other Acura models (MDX/TLX) and was done to correct the intermittent sticking issue caused by uneven spring wear in the original valve design.
  Heads up: While this specific part number may not be for the ILX, it demonstrates a pattern of Acura identifying and correcting this specific failure mode with revised parts. When purchasing a replacement for the ILX, opting for the latest OEM revision or a reputable aftermarket brand is advisable over potentially old stock.

Model Year Variations Within This Range

• 2013-2015: These models used either the 2.0L (R20A) or 2.4L (K24Z7) engine. The common purge valve for the 2.0L is part number 36162-R1A-A01. The valve is located on the right rear of the engine.
• 2016-2022: Following the 2016 facelift, the ILX exclusively used the direct-injected 2.4L (K24W7) engine. This engine uses a different purge valve, part number 36162-5A2-A01.

Diagnostic Flowchart

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• U0401-68 — Electronic Parking Brake Error. Documented side effect on the ILX that triggers alongside P0441 when the purge valve fails, as the ECU interprets the EVAP fault as a broader system issue.
• P04F1 — EVAP system code reported by an ILX owner alongside P0441 after driving over snow, pointing to a potential purge valve or cracked line issue.
• P0455 — EVAP System Large Leak Detected. Mentioned in context as a code more commonly associated with a loose gas cap, which can also disrupt vacuum and trigger P0441.
• P0456 — EVAP System Small Leak Detected. Related to the diagnosis step of performing a smoke test to find small, hard-to-see leaks in the EVAP hoses or charcoal canister.

Frequently Asked Questions