where is the downstream oxygen sensors for a 2003 Ford Explorer?

Answer 1

One on each bank located by the transmission bell housing in the pipes below the exhaust manifolds. My neighbors V-8 explorer has 4 O2 sensors. So bank one the #1 spark plug side and bank#2 sensors are important too. Each o2 sensor has a different plug. And it is best to get the correct sensor from the Ford Dealer.

Answer 2

Here's some helpful information. The downstream O2 sensor are actually catalyst monitor sensors. They work just like oxygen sensors. On a 03 Explorer, the passenger side of the engine is bank 1. From the exhaust pipe going back, the first sensor in the pipe is the O2 sensor. It has a green connector. The O2 sensor monitors the oxygen in the exhaust. From there, there is the converter. Right after the converter is the catalyst monitor sensor. It has a blue connector. Now the reason for going after that sensor. The role of the cat monitor sensor is to verify operation of the catalyst system ability to hold oxygen. Most people go after replacing the due to DTC's retrieved from the PCM, P0420/P0430. Here's the clue, the cat monitors rarely ever fail. If you’re getting those DTC's you need to verify proper engine coolant temp. If the engine does not reach normal operating temp is a specific time, those DTC's may be set. If you have a v-6(4.0 lit SOHC), the thermostat have been know to literally fall apart. Look at the cooling temp before replacing parts that you don’t need to. Feel free to reply for further information.
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Answer 3

2003 Ford Explorer O2 Sensor

Answer 4

The oxygen sensors are always located on the exhaust pipe
just a short way from the exhaust manifold coming off the engine, they look sort of like a plug screwed in with a wire
coming out of the top centre.

Answer 5

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It is suppose to just unscrew. Using a wrench on the brass looking area. If it is just turning and not coming out chances are it is stripped out. Trying having someone use a prybar and apply slight upward pressure on it while you try unscrewing it. If the housing the sensor screws into it plastic becareful not to break it. This sensor works with your pcm also. So that the pcm can control the fuel tables telling the engine whether it needs to lean or richen the fuel mixture.

Answer 6

you have 4 o2 censer one on the manifold and one after the converter, On each side. hope this helps