# NOX sensor replacement procedure



## baked potato (Dec 27, 2019)

I'm in the process of replacing NOX sensor 2 on my 2014 with 170,000 miles. I found the instructions on the forum which were very useful. When I removed the old sensor it was very stuck I had to use heat and hammer to get it loose. When the old sensor came out the threads looked a little deformed. I've got it all back together. My question is about how the new sensor fits in the exhaust pipe. I tightened the nut that holds the sensor in. The sensor itself is still loose. I was expecting the sensor to tighten up when I tightened the nut. The sensor can be rotated. There is not any end play but it is definitely not tight. so my question is Is the sensor supposed to be tight or is it supposed to be able to rotate? Thanks in advance for advice !


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## MP81 (Jul 20, 2015)

It definitely should all be tight.


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## baked potato (Dec 27, 2019)

MP81 said:


> It definitely should all be tight.


thanks for the reply. i'll get a thread chaser and see if that helps


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## MP81 (Jul 20, 2015)

baked potato said:


> thanks for the reply. i'll get a thread chaser and see if that helps


Yup - that's probably your best bet. The two times I've replaced our NOx2 sensor, it has required a lot of heat from the MAPP torch, so it's not a surprise it mucked the threads up too.


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## BDCCruze (Jul 12, 2017)

I had a SES for this a year or two ago and it went off and never came back. Is that normal? I still have the part but I'm waiting for it to actually fail.


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