tdc 0466
#2
09-29-2010, 10:20 AM
The cars fuel tank is not vented to atmosphere but is a closed system. Fuel tank vapors are not routed to the air but into a charcoal canister for storage. When the engine is running these vapors are then rerouted into the engine to be burned. This system is called Evaporation Emission Control System (EVAP).
This system requires various pressure sensors, valves, tubing, etc to work.
The cars computer monitors the performance of this system somewhat indirectly by using a pressure sensor.
The computer is programmed to know what the pressure sensor reading should be when the EVAP system is ON and OFF. If the pressure is not what is supposed to be this code is tripped (typically this means the pressure is now the same as atmosphere).
Basically it means there is one of the following issues: The control valve used to turn the system on and off (VSV) is not working, there is an air leak in the system (hose, canister) causing the pressure reading to be the same as atmosphere or bad pressure sensor.
Sometimes the fuel tank cap is not tightened enough. Check the cap.
As to how to fix it.
Suggest you first read up on post about this code such as the one below:
http://img.toyotanation.com/forum/sh...d.php?t=156027
In the past typically issues were bad VSV, cracked canister or hose. Seldom a bad pressure sensor. Many people just replace the canister, VSV and pressure sensor as a unit.
This system requires various pressure sensors, valves, tubing, etc to work.
The cars computer monitors the performance of this system somewhat indirectly by using a pressure sensor.
The computer is programmed to know what the pressure sensor reading should be when the EVAP system is ON and OFF. If the pressure is not what is supposed to be this code is tripped (typically this means the pressure is now the same as atmosphere).
Basically it means there is one of the following issues: The control valve used to turn the system on and off (VSV) is not working, there is an air leak in the system (hose, canister) causing the pressure reading to be the same as atmosphere or bad pressure sensor.
Sometimes the fuel tank cap is not tightened enough. Check the cap.
As to how to fix it.
Suggest you first read up on post about this code such as the one below:
http://img.toyotanation.com/forum/sh...d.php?t=156027
In the past typically issues were bad VSV, cracked canister or hose. Seldom a bad pressure sensor. Many people just replace the canister, VSV and pressure sensor as a unit.
