P0450 Evaporative Emission Control Syst

Have a 1998 4runner 2WD 4 Cyl got the following fault codes:

P0450   Evaporative Emission Control System Pressure Sensor Malfunction

P0441 Evaporative Emmission Control System Incorrect Purge Flow

P0446 Evaporative Emmission System Vent Control Circuit Malfunction

No one seems to be able to tell me what exactly is wrong ....just alot of guesses....anyone here had these problems?

 

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Ihavean 01 and am getting the same PO446 code on mine. Looking for some info also. Dealer (Lexus) as I bought it used, has sort of thrown up their hands and blaming it on the aftermarket intake it has???? (not buying it) The thought from them is the hoses are not routed correctly,they are downstream of the mass air flow switch. I do not know yet if they should be up or downstream of the switch. Talking with local Toyota dlr svc guy did not think it was to blame. Any ideas?? Thanks.

hello there,  i have same problem code #po441,po446.   please let me know if you know the result!  thx,

anyone know how to fix this problems; code # p0446 evaporative emission control vent control circuit?  also code # po441 evaporative emmission control system incorrect purge flow?  if any one have any idea please let me know!  thx!!!!!!!!! 

Oh yes, keep getting the same two codes  PO 440 and PO 441  Evap malfunction and Incorrect Purge flow.  I clear it and it comes back.  Gas cap IS on tight.  We changed O2 sensor and solenoid and it is still coming on.  This is aggrevating. 

P0440 is a gas tank vapor leak
p0441 is incorrect purge flow
p0446 is directly related to the charcoal canister...
Replace the canister and all your problems (codes) will go away (after all codes have been erased from ecu memory of course)..