Q45 Check engine light, Knock or O2 Sensor?

[rodneydiller]

1996 Q45 w/ 133k. While driving on a long trip, my check engine light came on. Took it to Autozone for their free check engine diagnosis. They said the error code meant it was either the O2 sensor in front of the catalytic converter, or the knock sensor. Well, here's my questions. Is one or the other a more likely culprit? If it is the front 02 sensor, is there a way to tell if it is the left or right...or do I just bite the bullet and replace them both? If I paid the big bucks for dealer diagnosis, can they be more specific with their computer? I've got to go on another 1000 mile trip on Wednesday. Is this a must fix before, or can it wait? Even before the check engine light came on, it felt like I had lost a couple of cylinders. Any help is greatly appreciated!

[maxnix]

Have the O2 sensors ever been replaced? If not, they are over due. Think there are 4 on OBD II VH45DE.

KS may be in the same boat but far more labor intensive. I wuld presume the dealer's trained technician could tell you which, but do not know for certain. The 1996 is a rare bird.

Oh, and welcome to the board!

[Q451990]

There are different codes for knock sensors and O2 sensors, so I would guess that the autozone scan either saw both - or the tester was confused for some reason.

Go ahead and replace the O2 sensors as a pair - as Brian mentioned, it's time just as general maintenence. Might take it in for a Consult scan to check for sure, and have the sensors replaced while you're there. I wouldn't try the aftermarket cut & splice route for sensors on a Q. If you are in to DIY, you can order them from http://www.everythinginfiniti.com or http://www.sparkplugs.com (for aftermarket "OEM Identical".)

It's enough of a pain to do that I didn't risk non-OEM on my Qs, but used the sparkplugs.com unit on my truck that takes about 10 minutes...

Heath