You are here:

Toyota Repair/emissions in a 99 seinna


hi my 99 sienna has p0441,p0442 p0446 codes,I cleared the codes and went for inspection ,it failed because the cat-not ready and evap-not ready.I drove around about 180 miles and it still is not ready.the cat and oxy-sensors was changed 5 yrs ago .this vehicle has 244000 you have any ideas for me as to what is going on and what might need repairing.

Hello, those codes are for an evap system malfunction, just clearing the codes and not fixing the cause will not let the monitor for the evap system complete, there is most likely a pending code which prevents the system monitor from completing and passing or failing, the most common cause for all three codes are a gross leak, possibly fuel filler cap or a hose off at the canister or under the hood. To force the converter monitor to run start with the car cold then after warm up do a series of acceleration and deceleration drive cycles, the cat may not be getting up to temperature to cause the monitor to run, if it was an aftermarket cat it may be due to be replaced again, if the emission readings were within limits then it is only necessary to get the cat monitor to run and complete and to fix the cause of the evap codes, try first by replacing the gas cap, inspect the fuel filler tube for damage and the evap system hoses, if this doesn't fix it then it will need further testing.  

Toyota Repair

All Answers

Answers by Expert:

Ask Experts


Ted Ritter


I have more than 28 years experience as toyota technician, I will be able to answer most questions related to the Toyota product line up to the present year models,I am located in the US but welcome questions from other regions of the world. When asking a question please provide specific information: year,model, engine,transmission information. Provide as much information as possible including a brief repair history if possible. I have been a volunteer here for more ten years an have answered over 16,000 questions helping Toyota owners with their problems and save thousands of dollars without any compensation, some of my answers are published on many other websites including google and various automotive forums. DONATIONS ARE VERY MUCH APPRECIATED, IF YOU HAVE RECIEVED HELPFUL INFORMATION PLEASE MAKE A DONATION. AS OF TODAY (JULY 22, 2014) ALL REQUESTED GRAPHICS, ILLUSTRATIONS, DIAGRAMS, PHOTOS, WILL REQUIRE THE MINUMUM DONATION UP FRONT.


Toyota technician since 1979,expert in electrical systems,OBD systems,engine repair, driveability problems,EFI systems,ASE certified,Toyota master technician.
Certified Hybrid Vehicle technician.

Toyota master technician, ASE certified in eight catagories, Hybrid vehicle certified. Toyota technical training: Engine Automatic transmission Manual transmission Drivetrain Electrical systems Brakes and chassis Air conditioning Engine performance and diagnostics Hybrid systems

©2017 All rights reserved.