Oxygen Sensor There are actually (4) O2 sensors on your truck. If you look inside the wheel wells behind the fender liner, right about where the frame is one O2 sensor, the other is underneath the truck about half way back in relation to the transmission. If you see where the exhaust joints together, you went about 6" too far.
When you start looking at the O2 sensors, they are normally numbered something like "Bank 1 Sensor 1" Bank 1 is on the passenger side; Bank 2 is on the driver's side. Sensor 1 is the upstream sensor (near the frame, between the block and the cat) and Sensor 2 is near the Y-pipe (downstream of the cat).
Normally it is the upstream sensors (sensor 1) that go first. They see the harshest conditions. You will need; Oxygen Sensor Socket Anti-Seized Penetrating Oil Sometimes it will take 15 minutes or take a few hours it depends on your luck…
In a Ford Expedition : Bank 1 is the passenger side of the engine Sensor 1 would be close to the engine before the exhaust enters the catalytic converter ( upstream sensor )
Bank one is the side of the engine with cylinder number one. Position two is after the catalytic converter.
position 1 bank 1 would be on the header where cylinder number 1 is located. you can work your way back from there position 1 bank 2 would be the opposite exhaust manifold, followed by position 2 bank 1 would be the pre catalytic converter sensor, and position 3 bank 1 would be post catalytic converter.
P1131 on an Expedition is a mass air metering error, not to be confused with a mass air sensor. The engine control module cannot see the bank one sensor one O2 sensor switch from lean to rich. Basically, the sensor is either bad or the wiring has a fault or short somewhere between there and the ECM.
bank one is where the number one cylinder is sensor one is before the cat and sensor two is after the cat
Bank one sensor two refers to the oxygen sensor. The bank one sensor two oxygen sensor is on the front side of the engine, after the catalytic converter.
bank one is close to the fire wall sensor one is before the cat
Bank one sensor one is above the converter.
In a Ford Expedition bank 1 is the passenger side of the engine , bank 2 is the drivers side
Bank one is the side that includes cylinder number one. Sensor two is post catalyst.
A 2001 Caravan with the 3.3L does not have a bank 2. Bank 1 sensor 1 is the one screwed into the rear exhaust manifold. Bank 1 sensor 2 is the one screwed into the side of the catalytic converter.A 2001 Caravan with the 3.3L does not have a bank 2. Bank 1 sensor 1 is the one screwed into the rear exhaust manifold. Bank 1 sensor 2 is the one screwed into the side of the catalytic converter.
Bank 1 is the bank that sits closest to the front of the vehicle. Bank one is the bank with cylinder # 1. You have 4 oxygen sensors, (bank 1 sensor 1, bank 1 sensor 2, bank 2 sensor 1 and bank 2 sensor2). Follow the exhaust from the head of bank 1. The first sensor you come to is sensor 1, the second is sensor 2.