the dealer who i bought my max from told me after i bought the car that the error light i was getting was due to the Knock Sensor. I asked him to repair it and he says that it doesn't affect the car. reading the faq and what not, it lowers your mileage. i reset the computer and i had great mileage for a week till the light came on again. dealer says it was because of a dead battery and the computer mistakes that error for knock sensor. the nissan dealer agreed and said that the knock sensor rarely malfunctions or needs to be changed. what do you guys think?

 

Knock sensor should not trigger your CEL, they're bs you, check the codes on the car and see what it is. Read the FAQs how to and what they mean.

 

Knock sensor does effect the car....but not in a way that 95% of the people who own maximas would notice.

A bad knock sensor alone will almost never trigger the CEL. It is almost always either a ghost code (when there is a problem and a code but no CEL) or it shows up with another code. Many times, for whatever reason, if two codes are present and one is a knock sensor code fixing the other problem and clearing the codes will take care of the knock sensor code. Either way I would always clear the codes the first time the CEL comes on and see if the codes reappear.

In short:

A bad knock sensor will effect the performance of the car
A bad knock sensor alone will not usually trip a CEL
Always fix the non-knock sensor code first
Always clear codes and see if they come back before fixing things.