AutoCodes – Generic – P1440

P1440 Code - Evaporative Emission Control System Small Leak

Quick Answer

This diagnosis detects leaks in the Evaporative Emission (EVAP) purge line using of vapor pressure in the fuel tank. Common causes include Fuel filler cap remains open or fails to close, Foreign matter caught in fuel filler cap, Incorrect fuel tank vacuum relief valve. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P1440 indicates Evaporative Emission Control System Small Leak.
Common causes: Common causes include Fuel filler cap remains open or fails to close, Foreign matter caught in fuel filler cap, Incorrect fuel tank vacuum relief valve.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 49,170

How popular is this code, among other codes? Medium

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 22, 2019

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P1440 Description

This diagnosis detects leaks in the Evaporative Emission (EVAP) purge line using of vapor pressure in the fuel tank. The EVAP canister vent control valve is closed to shut the EVAP purge line. The vacuum cut valve bypass valve will then be opened to clear the line between the fuel tank and the EVAP canister purge volume control solenoid valve. The EVAP control system pressure sensor can now monitor the pressure inside the fuel tank. If pressure increases, the Engine Control Module (ECM) will check for leaks in the line between the vacuum cut valve and EVAP canister purge volume control solenoid valve.

OBDII Code P1440 - Evaporative Emission Control System Small Leak - AutoCodes.com — P1440 Code - Evaporative Emission Control System Small Leak

What does this mean?

What are the Possible Causes of the DTC P1440?

Fuel filler cap remains open or fails to close
Foreign matter caught in fuel filler cap
Incorrect fuel tank vacuum relief valve
Incorrect fuel filler cap used
Leak is in line between intake manifold and EVAP canister purge volume control solenoid valve
Foreign matter caught in EVAP canister vent control valve
EVAP canister or fuel tank leaks
EVAP purge line (pipe and rubber tube) leaks
EVAP purge line rubber tube bent
Blocked or bent rubber tube to EVAP control system pressure sensor
Loose or disconnected rubber tube
EVAP canister vent control valve and the circuit
O-ring of EVAP canister vent control valve is missing or damaged
EVAP canister is saturated with water
EVAP control system pressure sensor
Absolute pressure sensor

How to Fix the DTC P1440?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

The most common cause for the P1440 code is a loose or missing fuel filler cap. Resecure or install the cap and reset the engine light. In some cases, the light will turn off by itself after a few days driving the vehicle. if the problem persistss replaced the gas cap.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1440 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P1440 code?

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Information for Specific Makes

P1440 Audi — EGR Valve Power Stage Open
P1440 BMW — Purge Control Valve Control Circuit Signal High
P1440 Honda — Motor Power Inverter (MPI) Module Output Circuit Malfunction
P1440 Hyundai — EVAP System Vent Circuit
P1440 Infiniti — Evaporative Emission Control System Small Leak
P1440 Jaguar — Evaporative Emission Canister Purge Valve Open
P1440 Lexus — Secondary Air Injection Vacuum Switching Valve Circuit Malfunction Bank 1
P1440 Nissan — Evaporative Emission Control System Small Leak
P1440 Subaru — Fuel Tank Pressure Control System Low Input
P1440 Toyota — Secondary Air Injection Vacuum Switching Valve Circuit Malfunction Bank 1
P1440 Volkswagen — EGR Valve Power Stage Open

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.