On the 2004 Toyota Sequoia, the P0441, P0446 and P2418 are recorded by the ECM when there is an evaporative emissions leak or when there is a malfunction in either the Purge Solenoid (VSV for EVAP), the Vent Solenoid (VSV for Vapor Pressure Switching), or in the EVAP Vapor Pressure Sensor
Diagnostic trouble code P0455 points to an EVAP System Large Leak Detected.
So- begin by triple-checking the Fuel Cap. Check the underside of the fuel cap for any cracks or signs of defects that may keep the cap from sealing correctly. If there are any doubts about the inspection of the cap, replace it. Keep in mind, you will need a cap that meets OE Specs. Those “universal” or “locking” fuel caps sold at after market parts stores do not meet OE specs, and will not seal the system correctly.
IF the Cap checks ok, test the VSV’s:
VSV EVAP: 37 – 44 Ohm at 20 °C (68 °F)
Pressure Switching VSV: 25 – 30 Ohm at 20 °C (68 °F)
If the VSV’s check ok, the problem will lie in the Vapor Pressure Sensor. Make sure to check all the vacuum lines between the VSV’s for any cracks, holes or missing connections.
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