It is the upstream(before catalytic converter) oxygen sensor on the exaust that comes off the front engine bank.
Where are the Bank 1 Sensor 1 oxygen sensor on a 1998 ford explorer?
o2 sensor Bank 2 sensor 2
bank 1 is the side of motor near the firewall that's where the #1 plug is
closest sensor to the motor
Left side of car, first sensor towards the front.
On a 1998 Ford F-150 or Ford Expedition , 5.4 Bank 2 is the drivers side of the engine Sensor 1 would be close to the engine BEFORE the exhaust enters the catalytic converter
Trouble code P0135 means:O2 sensor heater circuit malfunction (Bank 1 Sensor 1)
firewall #1-----#2-----#3 ( Bank 1 ) #4-----#5-----#6 ( Bank 2 ) front of Ford Windstar > driver
Bank #1 is the passenger side of the engine , and sensor # 2 is in the exhaust after the catalytic converter ( downstream )
Bank 1 on the 4.6 liter Ford is the passenger side of the engine Sensor 1 is in the exhaust before the catalytic converter ( upstream )
On a Ford Windstar , V6 engine : firewall 1-----2-----3 ( Bank 1 ) 4-----5-----6 ( Bank 2 ) front of vehicle > driver Bank 2 , Sensor 1 would be close to the engine BEFORE the exhaust enters the catalytic converter
In a 2001 Ford Windstar : firewall 1-----2-----3 ( Bank 1 ) 4-----5-----6 ( Bank 2 ) front of vehicle > driver