Took my 2005 X-type in for a smog test and failed, coming back with the P1647 code. They wanted to replace a single sensor for $900 at what was just a small shop, so I took it to a trusted mechanic, and replaced the bank 2 (left) upstream AND downstream sensors, with Bosch parts. The check engine light from before is still on, and failed another test. Has anyone else had similar issues? Is there anything else I should be checking? One Jag guy told me the Bosch parts were crap, anyone else have similar opinions? Thanks!

John

 

Deuces, based on the fact that the O2 sensor didn't fix things, you are left with 2 other possibilities. The more likely one being that the wiring going to the sensor is damaged. I would be looking at the wire bundle that runs right behind the battery box for any signs of damage. You can hand over hand the wiring from the O2 sensor (the one in the front of the engine nearest the front bumper) and follow it around to the driver's side. If you see exposed copper, then that would be a good sign that is where your problem is. Your other option is you have a problem with the ECM that is limited to just that one O2 sensor. Possible, but normally not a likely way for things to fail.

The other thing that you may want to have checked out is what the plug looks like where the O2 sensor plugs in. The pins should be nice and shiny silver in color. If they are gray/dull in color, then it is possible that is your problem as it is not allow proper connection and that is causing the computer to see it as a problem.

 

Looking at the wires in front of the battery, everything looks fresh, silver, and unharmed. You are saying I need to follow the wires behind the battery, meaning underneath and going towards the windshield? Everything from what I saw was in tact and undamaged that was exposed from an overhead view.

 

While the logical and rational analysis that Thermo has provided will most likely lead to the solution to your problem, don't forget the devious and irrational minds that would tell you that your shop may have put in the wrong part, mixed the parts up, or one of the replacement sensors was bad right out of the box. And I would steer clear of any shop that asks $900 to change an o2 sensor!
BTW, I've changed o2 sensors with Bosch replacements and had no problems.

 

Deuces, I am talking about having you hand over hand the wiring from the sensor to where it goes through the firewall. It is a common problem that rodents will get into the engine bay and snack on the wiring, leading to problems like you are seeing. So, if you find the plugs near the radiator for the O2 sensors and then follow it back to the windshield area.

 

The two up stream and down stream sensor are difference, I believe the up stream sensor was called air fuel mixture sensor, it look slightly difference from down stream, if you replace it with O2 sensor the code won't go away.

 

Old thread you know....