P1440 Code failures by brands


Description of DTC code P1440

The Evaporative Emissions Control System (EVAP) prevents fuel vapors from passing into the atmosphere and causing damage to the atmosphere. Instead, the vapor contained in the fuel system is sent back to the engine through the intake manifold.

EVAP diagnostics detect a leak in the purge line. To do this, it uses vapor pressure in the fuel tank. The EVAP tank vent control valve is closed to block the purge line. Consequently, the bypass valve opens to clear the line between the tank and the solenoid, controlling the purge volume of the canister. Then, the pressure sensor of the EVAP control system monitors the pressure inside the fuel tank. In case the pressure increases, the ECM (Engine Control Module) checks for leaks in the line between the vacuum shut-off valve and the purge control solenoid.

The P1440 OBDII fault code P1440 is set when the EVAP Control System is leaking, causing the EVAP Control System to malfunction.

Symptoms of fault code P1440

  • Check Engine light illuminated.
  • Strong gas odors are perceived.
  • Reduced fuel efficiency.

Causes of OBD2 P1440

The P1440 OBD2 diagnostic code is stored for these reasons:

  • The fuel tank cap may not close properly.
  • Several weird stuff may be trapped in the plug.
  • The fuel tank relief valve may be damaged.
  • The fuel tank cap used may not be the correct one.
  • The EVAP canister or fuel tank may be leaking.
  • The rubber hoses or EVAP purge line tubing may be broken.
  • The EVAP canister vent control valve circuit may be damaged.
  • The EVAP pressure sensor may be faulty.

Possible solutions of the DTC code P1440

To troubleshoot DTC P1440 OBDII, try this:

  • Consult the Technical Service Bulletins.
  • It is necessary to check if there are other DTCs set that indicate specific EVAP component failures. If so, make the diagnosis of those codes.
  • Check that the fuel tank cap closes completely. If it does not, you should verify that it is not due to blockage or damage. Fix if necessary.
  • Check the EVAP canister and fuel tank for any leaks. Repair if such condition is discovered.
  • Check the condition of the EVAP purge line piping, and check the piping for deficiencies caused by wear. If such conditions or other damages are found, make the appropriate adjustments.
  • Check the condition of the EVAP pressure sensor according to the manufacturer's specifications. If you determine that it is damaged, replace it.

Codes related to P1440

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