Diagnostic Aids

WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

Knock sensor 1 and knock sensor 2 voltages should be around 0.25 volt at idle and up to around 2 volts at fuel cutoff in Park. If a short to voltage occurs on either wire, knock sensor voltage on scan tool will be slightly higher at idle, but may look normal as the engine is revved.

With the engine off, the voltages on the scan tool for each sensor should be the same. If they are, DTC P0333 is most likely due to excessive engine noise and not a short to voltage.

DTC may set if knock sensor 2 is detecting excessive noise due to mechanical concerns. Possible causes are:

Valve lifter noise.
Belt tensioner loose.
Loose brackets.
Low octane fuel in high ambient temperatures under excessive loads.

ECM has ability to learn spark retard. If knock is present long enough, a reduced power condition may result due to maximum spark retard. Spark will eventually be returned to normal once knock condition is corrected.