Code Definition

P1440 — EVAP Small Leak

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Nissan

About P1440

P1440 is a manufacturer-specific powertrain diagnostic trouble code recorded for Nissan vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1440 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The evaporative emission (EVAP) system on Nissan vehicles captures fuel vapours from the fuel tank in a charcoal canister and purges them into the engine to be burned, while the Engine Control Module (ECM) periodically tests the system for leaks. DTC P1440 indicates the ECM has detected a small leak in the EVAP system during its leak diagnostic, meaning the sealed system cannot hold the expected pressure or vacuum. A common cause is a loose or faulty fuel filler cap, but any small leak in hoses, the canister, or seals can trigger it. The driver usually notices no driveability change, only the ...

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