I don't think you need to try anything else. It is useless and waste of your time and effort.The sensor has four terminals, two for the sensor and two for heater circuit. The code associated with your lovely van is the heater circuit broken. Do you think dirt/carbon deposite breaks the heater circuit? I have seen quite a few similar V6 cars had the same problem and replaced the sensor. Just replace the sensor. The sensor price varies from dealer to dealer. You can call for a price and then compare with aftermarket price. But don't get a universal one, get an OEM style one.
Bank 1 is the bank near the fire wall. The sensor is located in the exhaust not quite under the vehicle yet. The downstream one. The excess to it is limited. It may not be as easy to replace it as some other models. You can reach it from under the vehicle or take the driver front wheel off and use a long 22mm wrench. Remember, unhook the electrical connector before trying to break it loose.
