Test Two
WARNING: This page is about a different car, the 2009 Saturn Outlook, 2009 GMC Acadia, 2009 Chevrolet Traverse, and 2009 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
The ECM internally turns OFF the knock sensor signal circuits. The ECM then tests for any output response when no test signals are applied. If the ECM detects an output response, this DTC sets.