Diagnosis
If the PCM malfunctions in a manner which will not allow proper diagnosis of the KS circuits, DTC P0325 will set.If the PCM detects an excessive engine knock and is unable to eliminate the knock, DTC P0326 will set. This DTC indicates that the vehicle is operating with excessive amount(s) of spark retard.
DTC P0327 indicates that the PCM detects a noise channel below the learned value for the given engine speed and load. Problems encountered with the KS system should set a DTC. However, refer to Detonation/Spark Knock in Symptoms if no DTC sets, and the customer's complaint of detonation points to the KS system.