P0442 on 2007-2010 Infiniti M45: EVAP Small Leak Causes and Fixes

What's Unique About the 2007-2010 Infiniti M45

The 2007-2010 Infiniti M45 (Y50 generation) is highly susceptible to this code due to two main factors highlighted by an official manufacturer TSB and extensive owner experiences. First, a simple loose gas cap is the most common trigger, a point Infiniti emphasized in bulletin ITB09012F. Secondly, like many Nissan and Infiniti vehicles of this era, the EVAP canister vent control valve, located at the rear of the car on the passenger side, is a known weak point that often fails and causes these exact leak codes. Its location above the rear suspension makes it vulnerable to road debris and moisture, leading to solenoid failure.

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 (in rare cases, often when parked in a garage)
• Inability to pass a state emissions inspection
• Difficulty starting the engine immediately after refueling (long crank time), which strongly points to a stuck-open purge valve

Most Likely Causes

1. Loose or Faulty Fuel Filler Cap 🔴 High Probability → Shop Fuel Tank Cap Infiniti issued TSB #ITB09012F specifically stating a loose fuel cap is a likely cause for P0442 on these vehicles. The rubber O-ring on the cap can also crack and harden over time, preventing a proper seal. It is highly recommended to use an OEM cap, as aftermarket caps are known to cause sealing issues.
   How to confirm: Remove the cap and inspect the rubber seal for any cracks, stiffness, or damage. When reinstalling, tighten it until it clicks at least 2-3 times. If the seal is damaged or the cap doesn't click, replacement is the only option.
   Typical fix: Tighten or replace the fuel filler cap. Use an OEM (Original Equipment Manufacturer) cap for best results. The OEM part number is 17251-9BA0B or a superseding number.
   Est. part cost: $25-$45
2. Failed EVAP Canister Vent Control Valve 🟡 Medium Probability → Shop Vapor Canister Vent Valve This valve is located at the rear of the car on the passenger side, mounted to the charcoal canister, and is exposed to road debris and moisture, causing it to corrode and fail. It's a very common failure point on Nissan/Infiniti platforms of this era, often getting stuck open or closed.
   How to confirm: The valve can be tested with a capable scan tool to see if it actuates. A DIY method involves removing the valve (it twists off the canister) and applying 12V power to its terminals to see if the solenoid clicks open and closed. If it's stuck or doesn't operate, it has failed. A user on a NICOclub forum confirmed this exact failure mode on their M45.
   Typical fix: Replace the EVAP canister vent control valve. The valve is located behind the passenger side rear wheel, above a plastic splash shield. The Dorman 911-503 is a common aftermarket replacement. 🎬 Watch: See this step-by-step vent control valve replacement walkthrough.
   Est. part cost: $70-$120
3. Cracked or Disconnected EVAP Hoses ⚪ Low Probability Over time, the rubber and plastic hoses that make up the EVAP system can become brittle from heat and age, leading to small cracks. This is more common on older, high-mileage vehicles. The small rubber elbow connectors are particularly prone to drying out and splitting.
   How to confirm: Visually inspect all accessible EVAP lines running from the gas tank, to the charcoal canister, and to the purge valve in the engine bay. A professional smoke test is the most effective way to find a hard-to-see leak. During a smoke test, the vent valve must be commanded closed with a scan tool, or its port must be plugged, to properly pressurize the system. 🎬 See this guide on common leak locations and easy fixes.
   Typical fix: Replace the cracked section of hose or the entire hose assembly. Ensure all connections are secure.
   Est. part cost: $10-$50
4. Failed EVAP Purge Volume Control Valve/Solenoid ⚪ Low Probability This valve is located in the engine bay and controls the flow of fuel vapors into the engine. It can get stuck open or closed, causing a leak code. A stuck-open valve is a common cause of long crank times after refueling.
   How to confirm: With the engine off, disconnect the hose from the intake manifold side and try to blow through it. If air passes, the valve is stuck open and needs replacement. It should be normally closed. You can also apply 12V power to its terminals to listen for a click.
   Typical fix: Replace the purge valve and ensure the electrical connector and hoses are secure. The OEM part number has been superseded multiple times, with 14935-JF02C being one possible replacement. 🎬 Watch: How to test and replace the EVAP purge valve.
   Est. part cost: $90-$160

Rare But Worth Checking

• Cracked Charcoal Canister: → Shop Vapor Canister The plastic housing of the canister itself can develop cracks from road debris impact or age, creating a leak. This is usually found during a smoke test after all valves and hoses have been checked.
• Leaking Fuel Tank or Filler Neck: → Shop Fuel Tank Rust or corrosion on the fuel filler neck where the gas cap seals, or on the fuel tank itself, can cause a P0442 code. This is more common in regions that use road salt and would be visible upon inspection.

Diagnosis Steps

1. Read the code with an OBD-II scanner to confirm P0442 is present.
2. Check the gas cap. Remove it, inspect the seal for cracks or damage, and reinstall it, ensuring it clicks multiple times.
3. Clear the code with the scanner and drive the vehicle for several days to see if the light returns. Many EVAP monitors only run under specific conditions (e.g., after the vehicle has sat overnight).
4. If the code returns, perform a visual inspection of all visible EVAP hoses and lines under the hood and near the rear of the vehicle for obvious cracks or disconnections. Pay close attention to rubber elbow fittings.
5. Locate the EVAP canister vent control valve at the rear of the vehicle, behind the passenger-side rear wheel and a plastic splash guard. Inspect its wiring and consider testing it for functionality by applying 12V power.
6. Locate the EVAP purge valve in the engine bay and test it to ensure it is not stuck open by attempting to blow through it (it should be closed with the engine off).
7. If the leak source is still not found, the most effective next step is to have a professional perform a smoke test. This involves injecting pressurized smoke into the EVAP system to visually identify the source of the leak.

Parts You'll Likely Need

• Fuel Filler Cap (OEM #17251-9BA0B) — This is the most common cause of P0442 on this vehicle, as confirmed by Infiniti TSB ITB09012F. The seal wears out over time.
  Trusted brands: Infiniti OE, Gates, Motorad, Stant
  OEM price range: $30-$45
  Aftermarket price range: $15-$25
• EVAP Canister Vent Control Valve (OEM #14935-JF01C) — A common failure point on Nissan/Infiniti vehicles of this era. It gets stuck open or closed, causing a persistent leak code. Its location makes it prone to failure.
  Trusted brands: Infiniti OE, Dorman (911-503), Hitachi, Standard Motor Products
  OEM price range: $90-$120
  Aftermarket price range: $60-$90

Related Codes That Often Appear With This One

• P0456 — P0456 indicates a 'Very Small Leak,' which is a slightly smaller leak than P0442. They are often caused by the same components (gas cap, vent valve) and may appear together or interchangeably as a leak worsens or improves.
• P0455 — P0455 indicates a 'Gross Leak.' If a component like the vent valve fails completely or the gas cap is left off entirely, the system may log a P0455 alongside or instead of the P0442.

Technical Service Bulletins (TSBs) & Recalls

• ITB09012F: States that a loose fuel fill cap may be the cause for EVAP leak codes P0442, P0455, and P0456. It advises technicians to check the cap before beginning extensive diagnostics.

Platform-Specific Known Issues

• Per TSB ITB09012F, a loose fuel filler cap is a primary and highly common cause for the P0442 code on 2007-2010 Infiniti models.
• The EVAP Canister Vent Control Valve is located in a somewhat exposed position at the rear passenger side of the vehicle, making it susceptible to damage from road debris and moisture, leading to premature failure.
• A user on the NICOclub forums documented a detailed repair for a P0442 code on their 2006 M45, which was caused by a faulty EVAP canister vent control valve that was both leaking and sticking. They confirmed the part number as Nissan 14935-JF01C.