Over the weekend, the CEL popped up on my 97 Legacy. When I went to get it checked out at the local advanced auto and the code was 325 - Knock sensor. So, I decided to buy an Actron scanner and double check the code, and it was still there and still knock sensor.

 

I then erased the code and it hasn't reappeared yet. How long after resetting the codes should the CEL come back on if the sensor is really faulty? I will keep an eye on it, but should I get ready to replace the sensor anyhow?

it all depends what code it is....i believe the knock sensor is a 2 trip code so if the problem happens on 2 consecutive drive cycles than the CEL will pop on.....i could be wrong on that though.......when the CEL was on for the knock sensor did you feel like a lack of power or anything?

The code was P0325, and there was no power loss that I felt. The light came on when I got stuck in stop and go traffic. I will continue to monitor it, but if it is a 2 drive cycle code, I will know when I go home today.

 

it all depends what code it is....i believe the knock sensor is a 2 trip code so if the problem happens on 2 consecutive drive cycles than the CEL will pop on.....i could be wrong on that though.......when the CEL was on for the knock sensor did you feel like a lack of power or anything?