P1440 on 2000-2003 Nissan Maxima: EVAP System Small Leak Causes and Fixes

What's Unique About the 2000-2003 Nissan Maxima

On the fifth-generation (A33B) Maxima, the P1440 code is very frequently traced to components at the rear of the vehicle. The EVAP charcoal canister and the solenoid valve mounted directly to it are located behind the driver's side rear wheel, where they are exposed to road salt and moisture. This leads to heavy rust on the solenoid and its mounting bolts, seized components, and cracked plastic housings. Owners often find that one or both of the 10mm bolts for the control valve rust and break off in the canister, forcing the replacement of both parts. This issue is so common that many forum users recommend buying the canister and solenoid together from the start.

Symptoms You May Notice

• Check Engine Light is on
• A faint smell of gasoline, particularly around the rear of the car.
• Possible hissing sound from the rear driver's side wheel well area shortly after starting the car
• Difficulty refueling or the gas pump nozzle clicking off repeatedly (less common).
• Slightly reduced fuel economy.

Most Likely Causes

1. EVAP Canister Purge Volume Control Solenoid Valve Failure 🔴 High Probability The valve is mounted on the EVAP canister, which is located under the car behind the driver's side rear wheel. It is exposed to the elements, causing the metal valve body and its mounting bolts to rust severely and fail. The O-ring seal for the valve can also degrade, causing a leak.
   How to confirm: Locate the valve on the EVAP canister. Disconnect the electrical connector. Use a power probe or jumper wires from the battery to apply 12 volts directly to its two pins; a healthy valve will make an audible 'click'. If it doesn't click, it is seized. You can also use a vacuum pump on the ports to see if it holds vacuum when closed and flows when 12V is applied. Visual inspection for heavy rust is also a strong indicator. With a multimeter, the coil resistance should be approximately 20-30 ohms.
   Typical fix: Replace the EVAP Canister Purge Volume Control Solenoid Valve. It is often sold with a new O-ring. Be extremely careful with the mounting bolts, as they are likely to break. Soaking them in penetrating oil (like PB Blaster) for hours or even days beforehand is highly recommended.
   Est. part cost: $100-$175
2. Cracked EVAP (Charcoal) Canister 🔴 High Probability The plastic canister body and its hose nipples can become brittle with age and develop cracks. It is also very commonly damaged when trying to remove a rusted, seized purge volume control solenoid valve, as the bolts break off inside the canister's threaded inserts.
   How to confirm: Visually inspect the entire canister for cracks, especially around the mounting points for the solenoid valve. If a bolt has broken off, the canister is likely compromised. A smoke test is the most effective way to confirm a crack if it's not visible.
   Typical fix: Replace the entire EVAP canister assembly. This is often done at the same time as the solenoid valve due to the high probability of the bolts breaking.
   Est. part cost: $150-$250
3. Cracked or Disconnected EVAP Hoses 🟡 Medium Probability The small rubber vacuum hoses connected to the EVAP canister and purge valve become dry and brittle over time, leading to cracks and vacuum leaks. This is common on any vehicle of this age.
   How to confirm: Visually inspect all accessible EVAP hoses for cracks, especially at the ends where they connect to fittings. Wiggle the hoses to see if cracks appear. A smoke test will pinpoint the exact location of a hose leak.
   Typical fix: Replace the cracked section of hose. It is often inexpensive to replace all accessible small-diameter vacuum hoses at once.
   Est. part cost: $5-$20
4. Loose or Faulty Gas Cap ⚪ Low Probability While a common cause for EVAP codes on any car, it's less specific to P1440 on this Maxima, which usually points to the rear components. However, it's the easiest check. Aftermarket gas caps are a known source of issues.
   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 or damage. If the seal is worn, the cap cannot create a proper seal.
   Typical fix: First, try reinstalling the cap. If the code returns, replace the gas cap with a new OEM part for the best seal. Many forum users report that aftermarket caps do not seal correctly and cause the code to persist.
   Est. part cost: $20-$40

Rare But Worth Checking

• Rusted Fuel Filler Neck: In areas with heavy road salt use (the 'Rust Belt'), the metal fuel filler neck can rust through, creating a leak in the EVAP system. This is a more involved repair but is a known issue on older vehicles in these climates. A smoke test is the best way to identify this leak.

Diagnosis Steps

1. Read the code with an OBD-II scanner to confirm P1440 is present.
2. Inspect the gas cap. Ensure it is an OEM cap, is tightened until it clicks 3 times, and the seal is not cracked or hardened. Clean the filler neck sealing surface. Clear the code and drive to see if it returns.
3. Gain access to the EVAP system by removing the driver's side rear wheel and any plastic splash shields.
4. Visually inspect the vacuum hoses around the EVAP canister for any obvious cracks or disconnections. Pay close attention to the hose ends.
5. Inspect the plastic body of the EVAP canister itself for any visible cracks, especially around the solenoid mounting area.
6. Test the EVAP Canister Purge Volume Control Solenoid Valve. Disconnect the electrical connector. Using a power probe or fused jumper wires, apply 12V power to the two pins. Listen for a distinct 'click'. No click means the valve is bad and must be replaced.
7. If you plan to remove the solenoid, soak the two 10mm mounting bolts extensively with penetrating oil (PB Blaster, Kroil, etc.) for several hours before attempting removal to reduce the chance of them breaking.
8. If no obvious faults are found, perform a smoke test. Introduce smoke into the EVAP service port and look for smoke exiting from a cracked hose, the canister, the solenoid valve, the gas cap, or the fuel filler neck area.

Parts You'll Likely Need

• EVAP Canister Purge Volume Control Solenoid Valve (OEM #14935-5M00B) — This is the most common failure point for P1440 on this vehicle due to its location and susceptibility to rust and seizure. The OEM part has been superseded multiple times, with previous numbers including 14935-5M000, 14935-5M001, 14935-5M00A.
  Trusted brands: Nissan (OEM), Standard Motor Products, Dorman (P/N: 911-503)
  OEM price range: $120-$175
  Aftermarket price range: $45-$90
• EVAP Charcoal Canister (OEM #14950-4L60A) — The plastic canister can crack from age or get damaged during the removal of a seized solenoid valve. It is often replaced out of necessity when the solenoid bolts break. The OEM part number 14950-4L60A replaces the older 14950-4L600.
  Trusted brands: Nissan (OEM)
  OEM price range: $180-$290
  Aftermarket price range: $100-$160
• Gas Cap (OEM #17251-79960) — A worn gas cap seal is a simple but possible cause for any EVAP leak code. Using a non-OEM cap is a frequent cause of persistent EVAP codes on this platform.
  Trusted brands: Nissan (OEM)
  OEM price range: $25-$40
  Aftermarket price range: $15-$25

Related Codes That Often Appear With This One

• P1448 — P1448 specifically points to the EVAP Canister Vent Control Valve. If you have both codes, the Factory Service Manual recommends diagnosing P1448 first as its fault can trigger the P1440 code.

Technical Service Bulletins (TSBs) & Recalls

• While no TSBs directly address P1440 on this specific model, general EVAP system TSBs for Nissans of this era exist. However, the community consensus points overwhelmingly to the canister-mounted solenoid as the primary cause, making TSBs less critical for this specific diagnosis.

Platform-Specific Known Issues

• The 10mm bolts holding the purge volume control solenoid to the canister are notorious for rusting and breaking during removal. Many owners advise to just assume they will break and order the canister and solenoid together to save time and frustration.
• A user on Maxima.org shared a typical experience: 'I just replaced the purge valve and evap canister and that fixed the problem. I had to replace the canister because one of the bolts that attaches the valve to the canister broke off in the canister and removing it damaged the canister.'
• Another user confirms: 'Trying to remove vent control valve from canister will just break the screws 99% of the time.'

Mechanic-Grade Diagnostic Values

• EVAP Canister Purge Volume Control Solenoid resistance — expected: 20 - 30 Ohms at ~68°F (20°C). Failure: An open circuit (infinite resistance) or a value significantly outside the expected range indicates a bad coil.
• Voltage at EVAP Canister Purge Volume Control Solenoid harness — expected: 12V (Battery Voltage) with ignition key ON. Failure: No voltage indicates a break in the wiring, a blown fuse, or an issue with the ECM driver circuit.

Scan Tool Commands That Help

• Nissan CONSULT-II: Navigate to 'DTC WORK SUPPORT', select 'EVAPORATIVE SYSTEM', then 'EVAP SML LEAK P1440'. — This is a guided diagnostic test within the factory scan tool to confirm if a small leak is present after initial checks (like the gas cap) have been performed.
• Professional Bidirectional Scanner: EVAP Purge Valve/Solenoid activation test. — Use this command to manually open and close the solenoid to verify its mechanical function. You should hear an audible click when the command is sent. This helps differentiate a failed solenoid from a wiring issue.

Wiring & Ground Locations

• EVAP Solenoid Harness — In the driver's side rear wheel well, behind a small plastic triangular cover. Follow the harness from the EVAP canister toward the front of the car.. This section of the harness is exposed to road salt and moisture, and is a known chafe/corrosion point. A wire can break inside the insulation, causing an electrical failure for the solenoid that will not be found with a smoke test.
• Ground Check — Various points on the chassis. The Factory Service Manual specifies checking continuity between sensor/component ground wires and a known good engine or chassis ground.. A bad ground connection for the EVAP system pressure sensor or solenoid can cause erroneous readings and trigger the P1440 code. For example, the FSM diagnostic procedure for a related code involves checking continuity between terminal 3 of the EVAP pressure sensor and engine ground.

Real Owner Repair Stories

• Maxima.org forum user 'HomerMAC' (2000-2003 Nissan Maxima (A32 chassis mentioned, but context implies A33)) — Persistent P1440 code after replacing other EVAP components.
  ❌ Tried (didn't work) Replacing various EVAP parts
  ✅ What actually fixed it Found a corroded and broken wire in the harness located behind a small plastic cover in the driver's side rear wheel well. The user soldered and shrink-wrapped the broken wire to restore the connection to the canister components.
• Maxima.org forum user 'Teddie18' (5th Gen Nissan Maxima) — P1440 code
  ❌ Tried (didn't work) Replacing gas cap with OEM part, Replacing several 1/4 inch EVAP hoses
  ✅ What actually fixed it Replaced the EVAP canister purge valve and the EVAP canister itself. The canister had to be replaced because one of the bolts holding the valve broke off inside it during removal, damaging the canister.
• Maxima.org forum user 'JAB 02 MAX' (5th Gen Nissan Maxima) — P1440 code
  ❌ Tried (didn't work) Replacing gas cap
  ✅ What actually fixed it Replaced both the EVAP canister and the vent control valve together. The user noted that attempting to separate the old valve from the canister will 'just break the screws 99% of the time'.

"I Checked Everything" — The Actual Cause

• A common scenario for this code is passing a smoke test but the code persists. A forum user's mechanic performed a smoke test and found no leaks, and activating all solenoids showed they were functioning. The actual cause in these cases is often not a physical leak, but an electrical issue. Another owner found the final culprit to be a corroded, broken wire in the harness leading to the rear canister assembly, a fault that is invisible to a smoke machine.

OEM Part Supersession History

• 14935-5M000, 14935-5M001, 14935-5M00A → 14935-5M00B — Part revision by manufacturer.
• 14950-4L600 → 14950-4L60A — Part revision by manufacturer.
• Dorman 911-502 vs 911-503 → N/A — Aftermarket part catalog variations.
  Heads up: A forum user reported that for their 2003 Maxima, the Dorman 911-503 did not have the correct two-bolt mounting provision, while the 911-502 was expected to fit. Buyers should visually confirm the mounting style of their original part before ordering an aftermarket replacement.

Diagnostic Flowchart

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used EVAP canister assembly from a junkyard can be a cost-effective option, especially if your original canister was damaged during solenoid removal. Given the high cost of the new assembly, a used part from a dry, salt-free region is a viable choice.

Donor-vehicle mileage cap: roughly under 100000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• Inspect the plastic canister body for any hairline cracks, especially around the solenoid mounting bosses.
• Check that the threaded inserts for the solenoid bolts are not stripped or cracked.
• Look for a donor vehicle from a dry climate to minimize rust on the solenoid.
• If possible, bring a 12V power source to test that the used solenoid 'clicks' before purchase.

OEM-only on this vehicle (don't cheap out):

• Gas Cap - Multiple forum and technical sources strongly advise using a genuine Nissan OEM gas cap, as many aftermarket caps fail to seal correctly, causing persistent EVAP codes.

Aftermarket brands forum-validated for this vehicle:

• Dorman (P/N: 911-503) - Widely available and frequently used, but verify mounting style.
• Standard Motor Products (SMP) - A reputable brand often cited as a quality alternative to OEM.

Real Owner Stories

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

Related OBD-II Codes

• P0442 — EVAP System Leak Detected (Small Leak). This code is frequently caused by the same faults that trigger P1440 on the Maxima, such as a cracked EVAP canister, a degraded solenoid O-ring, or brittle vacuum hoses.
• P0456 — EVAP System Leak Detected (Very Small Leak). Often points to a failing seal, such as the O-ring for the Purge Volume Control Solenoid Valve or a faulty gas cap seal, both of which are listed as potential causes for P1440.
• P0441 — EVAP System Incorrect Purge Flow. Since P1440 points to a fault with the Purge Volume Control Solenoid Valve, a valve that is stuck open or closed will directly cause an incorrect purge flow, leading to a P0441 code.
• P0455 — EVAP System Leak Detected (Large Leak). While P1440 is often associated with smaller leaks or valve failure, a severe crack in the plastic EVAP canister or a disconnected hose—both possible causes—could be interpreted by the ECU as a large leak.
• P0440 — EVAP System Malfunction. This is a general EVAP system fault code that can be set in conjunction with the more specific P1440 when the ECU detects a problem with the system's ability to hold pressure, stemming from the same common component failures.

Frequently Asked Questions