Some 2009-2010 Japan-built Toyota 4Runner, Camry, FJ Cruiser, Land Cruiser, Prius, Rav4, Highlander and Yaris models may exhibit a MIL on with DTC P2420 (evaporative emission system switching valve control circuit high). The charcoal canister has been updated to address the condition. Check with your Toyota parts source for the appropriate replacement part number.
1. Inspect VSV for proper power and ground circuits. Using TIS Techstream, perform the following checks with the Canister Pump Module Connector connected and back probe the pins to obtain the readings.
a. Check voltage between pin 9 (VLVB) and chassis ground. With the ignition on, voltage should read between 9 and 14 volts. If so, proceed to the next step.
b .Check voltage between pin 8 (VGND) and chassis ground. With the ignition on, voltage should read between 9 and 14 volts. If so, proceed to step C. If not, the vent valve is open. Proceed to step 2.
c. Using TIS Techstream, activate the VSV and check voltage between pin 8 (VGND) and chassis ground. If 9 to 14 volts are present, this bulletin does not apply. Inspect and repair wiring. If less than 1 volt is present, proceed to step 2.
2. Replace the charcoal canister assembly.