# rear 02 sensor where is it



## dirtking_4 (Jul 31, 2005)

i pulled the codes on my sister 97 altima limited edition. it showed code 77. i looked it up and found out it was the rear o2 sensor if i was looking at the right thing. anyways could somebody help me find the REAR o2 sensor on her car. im not a total noob its just that im not used to her car.

is their 2 o2 sensors because the only one i know of is the sensor off the exhaust manifold


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## metro273 (Sep 16, 2005)

dirtking_4 said:


> i pulled the codes on my sister 97 altima limited edition. it showed code 77. i looked it up and found out it was the rear o2 sensor if i was looking at the right thing. anyways could somebody help me find the REAR o2 sensor on her car. im not a total noob its just that im not used to her car.
> 
> is their 2 o2 sensors because the only one i know of is the sensor off the exhaust manifold


The rear O2 sensor is screwed into the CAT. Be careful when removing it though, the bung that holds the O2 to the CAT rusts badly and alot of times, this bung will break off, causing you to have to replace the CAT...


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## KA24Tech (Feb 2, 2004)

The rear O2 sensor is down below in the exhaust pipe next to the flex joint near the oil pan. To remove it I recommend spraying it with penetrating oil when cool and spray it again every 10 minutes for an hour then let it sit for a while longer. Break it loose with a 6 point box end wrench or an O2 sensor socket. When you put in the new one use a little anti-seize on the threads.

Troy


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## dirtking_4 (Jul 31, 2005)

KA24Tech said:


> The rear O2 sensor is down below in the exhaust pipe next to the flex joint near the oil pan. To remove it I recommend spraying it with penetrating oil when cool and spray it again every 10 minutes for an hour then let it sit for a while longer. Break it loose with a 6 point box end wrench or an O2 sensor socket. When you put in the new one use a little anti-seize on the threads.
> 
> Troy


thanks for the reply :cheers:


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