Ok my jaguar x type needs the oxygen sensor bank 2 replaced. It's throwing obd code 1647. I was told it's under the airbox and I was told it's on top of the catalytic converter so which one is it? I really need to replace the correct one. Thx to anybody that can clarify the correct location. Thx

 

Here's the layout for Bank referencing and Sensor locations:





Graham

 

P1647 is upstream oxygen sensor on bank 2. It is in the front of the engine. There are 2 sensors in the front. 1 on the manifold and 1 on the catalytic converter. You want the upper one on the manifold. Just under the airbox.

 

The upstream sensor is the one before the catalytic converter. Downstream is the one in the catalytic converter. Upstream reads air/fuel mixture and sends signal back to engine control unit to adjust fuel mixture. The downstream sensor simply determines if the catalytic converter is working correctly and not clogged or burning out.

The one you want is #1 in the diagram above on the radiator side of the engine in the exhaust manifold above the catalytic converter.

Another easy way to tell is the heated sensor (HO2S) in the exhaust manifold has a little heating element in it so that it comes up to temperature quickly and can send the correct reading to the engine computer much earlier. That's why the upstream/heated sensors are 4 wire and cost more than the downstream sensors that are 3 wire and cheaper.

 

Your right! I was mistaken. 1647 is upstream, I'll have to edit my post. Thanks

 

There are many problems which can show O2 sensor code. Pretty often replacing O2 sensor doesn't help.
There is a torch test for O2 sensor. Find description and check sensor before spending $100 or so for sensor.
I buy sensors for $16-18 and replace connector.

 

Than you all for your help going to replace it today. You all are a great help. Have a great weekend.