# 1996 Altima - OBD not available for Emissions Test



## jwenig (Mar 16, 2005)

I guess in 1996, this was the first year they started installing the OBD which houses information on Fuel Emissions information among other things. I have been to the Illinois Fuel Emissions Testing site two times already and both times, my OBD's information was not Ready.

This is the first time I have they have jacked into my OBD to get this information... And I am wondering if it ever worked to begin with. I took the car to the dealership and they said they are getting an error from the OBD that relates to the Knock Sensor. They want to replace the Knock sensor for $450 first, and if that is not the problem, then replace the OBD for $1600. 

OK, my first question is if the Emissions people can't read the OBD and it is returning "Not Ready", how come Nissian can read the errors?

Secondly, could the knock sensor be the culprit preventing the OBD from generating the information it needs for the emissions test?

Thirdly, I'm thinking of replacing this sensor myself... it appears to be on the engine block by the Oil Filter... anyone every change one of these suckers before, is it easy? The part is only $150.... They want $300 more in labor I guess... sounds like a lot for one small part to fix? Also, if I replace the part, do I need to reset the OBD somehow to clear the errors, or will it set automatically... How does this work?

Any answers to these questions would be greatly appreciated!

Jason


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## Asleep (Jan 19, 2003)

all altimas have some sort of an obd system. 93-94 was obd1 and 95-01 was obd2 and i believe that 02- are obd 3. if you have a parts store such as auto zone available to you, have them check the codes and clear them.


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## Agoudine (Feb 19, 2005)

When your OBD gives you Knock sensor trouble code it does not necessarily means that the knock sensor is bad and needs replacement. It can be caused by many things other than that.
I agree with "AsleepAltima". Go to autopart store to check and reset your trouble codes for FREE or do it yourself. You don't need any special equipment for that ,but a screw driver. Resat the memory first and see if the code will come back. As I told you in your other question ,buy Haynes repair manual. It will answer many of your questions about how to check trouble codes,replace knock sensor and much more.


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## KA24Tech (Feb 2, 2004)

Check all the fuses because the power to the OBD II Data Link Connector may not be there and the knock sensor replacement depends on the actual code. I ususally will test the sensor, as well as clean it and torque it correctly. I clear the code and drive it.

Troy


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