My friend just got this car and the Check Engine light is on. The guy he got it from said he'd had the computer scanned and the message was to replace the knock sensor. However, the car isn't knocking, no matter what kind of gas is used. If the knock sensor in NG, shouldn't it knock?
Does the computer actually detect a bad sensor? Or is it merely indicating that it's time to change the sensor after a certain number of miles? If the sensor is actually bad, why isn't the car knocking? Is it possible that when the computer detects a bad sensor it retards the timing so the engine can't knock, in an effort to protect the engine?
Also, how does one clear the computer of such messages, to make the light go out?