CARspec runs into interesting situations from time to time.  The story with this 2008 Camry Hybrid is no different.

The guest’s initial concern was that of a check engine light and malfunction code P0328, indicating a malfunction with the knock control system.  On all modern engines, the car’s computer listens to the engine through a specialized sensor used to detect abnormal combustion as it relates to the firing of the spark plug.  On these engines, the car changes the timing of when the spark plug fires to optimize fuel economy and power, using the knock sensor as a listening device to correct this timing.

The guest’s particular knock sensor malfunction code indicated the knock circuit was open – something that is either caused by a failed sensor or a wiring issue.  Upon inspection via removal of the intake manifold, we discovered this:

Mouse chewed

A mouse had chewed through the knock sensor’s wiring, leaving behind some corn and foam in the process.  We soldered in new wires, reinstalled the intake manifold with new gaskets, cleaned out the corn, and the car ran like new.  The pile of debris:

Corn pile