What is a p0440 trouble code and what to do to fix?

Answer 1

P0440 EVAP System No Flow During Purge Possible Causes Setting Conditions

• Charcoal canister is loaded with fuel or moisture
• Fuel filler cap is loose, cross-threaded, damaged or wrong part
• Fuel tank, fuel filler neck or fuel sending unit 'O' ring is leaking
• Fuel tank pressure sensor is damaged, disconnected or it failed
• Fuel tank vapor line(s) is clogged, damaged or disconnected
• Purge valve vapor line is clogged, damaged, or disconnected
• Purge or vent solenoid power circuit is open (check the fuse)
• PCM has failed

DTC�P0107, P0108, P0112, P0113, P0115, P0116-P0118, P0121, P0122, P0123, P0125, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1115, P1121 and P1122 not set, engine started, ECT and IAT sensors from 39-86�F and within 16�F at startup, vehicle driven at a steady speed less than 72 mph, system voltage over 10.0v, BARO sensor more than 75�kPa, fuel level from 15-85%, and the PCM detected the EVAP system was unable to achieve and maintain vacuum during the EVAP flow and leak test. Note: An Ultrasonic Leak Detector can be used to help detect a leak.

This code sets in 2 Trip(s).

Your most likely culprits are going to be a loose, damaged gas cap, vent or purge solenoid, evap canister, or fuel pressure sensor. Other than the gas cap, I believe all of these items are dealer only.