Question I have a 1997 expedition w/5.4L I've got a PO141 downstream heated O2 sensor heater circuit fault(bank 1). My question is which of the 4 sensors is it indicating is bad. This is the fourth time in 7-8 years i've owned it, that this has occured. Which is considered bank 1 and bank 2. I would like to check it over before it goes back to the dealer for another repair. thanks.
Answer The sensor in question is located after the catalytic converter on the passenger side. You are in luck, you should be able to tackle that one yourself. You will need to hit the sensor threads with a good soak of penetrating oil at least 30 minutes prior to removal, for ease. You will also need the specialty tool(s) available at all parts stores for around $15. Most even have a loaner tool program to get all your money back. Be sure and buy the OEM sensor, Universal sensors are way too much headache.
