trouble with code p0440


Original poster
Aug 17, 2012
hey guys, im new here in this great forum! i have a 02 GMC envoy SLT, 131K miles , im getting the code P0440, i replaced the gas cap , (got it from the dealer), then, a month later got it back again..
any ideas how to deal with this....
thanks guys , and again this is a great forum, lot of great info.......


Nov 20, 2011
Milwaukee, Wisconsin
:tiphat: Welcome:tiphat:

In case you haven't heard:

From WIKI answers via Google:

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.

Read more: What is a p0440 trouble code and what to do to fix


Original poster
Aug 17, 2012
well for what i can see in your answer, theres a lot of stuff that i need to check, wow...
thanks bro

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