Circuit Description
WARNING: This page is about a different car, the 2000 Saturn LW2 and 2000 Saturn LS2. However, it is still accessible from the selected car via links, so may be relevant.
ECM monitors a zero pulse and a test pulse from knock sensors to assure it still can detect a knock. This diagnosis runs once per 255 engine cycles after closed loop is reached. ECT greater than 102°F (39°C). This DTC indicates an error in the knock switch or knock evaluation circuit, both are internal to ECM.