I purchased a CanOBD2 code reader to see what the codes are so I can look into repairing the problem myself. The gas mileage may be off a bit but the car otherwise starts, runs, and drives normally at all speeds and under all conditions. The gas cap used to have pressure but now it doesn't, and I always make sure the cap is sealed properly (three ''clicks''). My friend used to drive it and he had a tendency to overfill the tank so it may have triggered the codes. The gas cap is the stock Toyota unit and I've never had it pressure tested. I don't want to replace it unless it's defective.
Since only 441 and 446 codes are present I'm thinking there's a bad valve/switch in the evap canister but wanted to check here first. How much of a job is it to repair this problem? I don't have a service manual so perhaps someone could post a diagram or direct me to a site where I could purchase a manual on the cheap since my budget is really tight right now.
Thanks sincerely for your help. :)
Hi Toyota Ed, Could you please send me the solution for the p0446 code issue on a 99 es300?
A. Diagnostics for PO441:
1. Remove Vacuum Hoses between EVAP VSV and Charcoal Canister and discard.
2. If there is a metal vapor pipe between EVAP VSV and Charcoal Canister, clean inside of vapor
pipe
3. Replace EVAP VSV and Charcoal Canister assembly with new parts.
4. Install new vacuum hoses between EVAP VSV and Charcoal Canister.
B. Diagnostics for P0446:
1. Inspect vacuum hoses and pipes between EVAP (Purge) VSV and Charcoal Canister for leaks.
2. Replace Vapor Pressure VSV and Canister.
NOTE :When performing diagnostics for an occurrence of a MIL "ON" condition, Diagnostic
Trouble Code (DTC) P0441 may be result of debris in Evaporative Emission Control System. This
may cause blockage of a vapor line, or a stuck VSV, as described in troubleshooting area of Repair
Manual.
Robert
Change your gas cap
SOURCE: p0440,p0441,p0446
These codes are all for the Evaporative Emissions System.
P0440- Evaporative emissions system fault- just saying there's something wrong with the system.
P0441- Evaporative emissions system- Incorrect purge flow- saying that the system isn't purging the raw fuel vapors (hydrocarbons- HC) as well as it should.
P0446- Evaporative emissions system- Control valve circuit low- there is a valve, usually located on the charcoal canister at the rear of the vehicle, that opens to allow fresh air to enter the evaporative emissions system as the engine vacuum purges the fuel vapors from the charcoal canister and closes when purge is not needed to prevent leakage of those fuel vapors to the atmosphere (HC is a greenhouse gas and is regulated as such by the fed gov't).
Given that you have the incorrect purge flow code and the control valve code together, my bet is that the vent control valve has failed (causing the P0446) and is not opening to allow fresh air into the system to displace the air from within the system that is being pulled to the engine. Since you have no fresh air entering the system, the engine will pull a vacuum on the system instead of the vapors "flowing" into the engine (causing the P0441).
I hope that this is helpful to you!!!
ASE Master Technician with L1 and X1 Certifications; Nissan Scope Technician; Chrysler Level 3 Silver Technician- 12+ years experience.
SOURCE: Code P0441 and P0446. What does it mean?
Both codes are with the EVAP SYSTEM, there are numerous items it could be. A repair shop that does Toyotas or the delaler would be the best to check it out for you. Its not anything that will leave you walking or disable the car.
SOURCE: 99 Camry, P0441 & P0446 codes
Sent it to you this morining. Hope that it helps. Thnaks for choosing FixYa to solve your issue.
Repair open or short in voltage feed circuit to Purge Solenoid.
Repair open in PCM purge command circuit.
Replace purge Solenoid.
Replace vacuum switch.
Repair restriction in Evap line or canister or soleniod.
Repair resistance in purge connector.
Replace PCM.
for p0442
Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
Otherwise, replace the gas cap, or
Inspect the EVAP system for cuts/holes in tubes/hoses.
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Hi! The solution provided by Bunnydawg is very good.
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