p0446indicates that self test has detected the evap systemhas excesive vacuum or vent control malfunction
possible causes are blockd or kinked hoses
purge valve stuck
filler cap not venting
vref open to ftp sensor
damaged ftp sensor
Continuous Memory Diagnostic Trouble Code (DTC) P0446 or P1450 indicates that Self-Test has detected the Evaporative Emission Control System has excessive fuel tank vacuum. Also, a DTC P0446 indicates a vent control malfunction.
Note: If the EVAP canister-CV solenoid and fuel tank assemblies are not accessible to perform the following step, GO to the Powertrain/Engine Group, Evaporative Emissions Section in the Workshop Manual for removal procedures.
the second issure is on dealing with the engeine
Are DTCs P1127, P1128 or P1129 present during KOER Self-Test?
Diagnostic Trouble Codes (DTCs) P0133 and P0153 indicate the response rate of the upstream HO2S(s) is below some calibrated window. The test measures the HO2S amplitude and output frequency. This is accomplished by superimposing a 1.5 to 2.5 Hz square wave over Lambse. The HO2S switching is monitored during this time to see if the calibration limit is met.
DTC/HO2S Reference List:
Does the measured value indicate greater than 614?