P0325

Circuit Description
The PCM contains integrated Knock Sensor (KS) diagnostic circuitry. Input signals from the knock sensors are used to detect engine detonation, allowing the PCM to retard Ignition Control (IC) spark timing based on the amplitude and frequency of the KS signal being received. The knock sensors produce an AC signal under all engine operating conditions. During engine operation, the PCM calculates the average voltage of each knock sensor's signal. If the PCM malfunctions in a manner which will not allow proper diagnosis of the KS circuits, DTC P0325 will set.

Conditions for Running the DTC
^ No TP sensor, VSS, CKP, MAF, or ECT DTCs are set.
^ Engine speed is between 1000 and 3000 rpm.
^ Throttle angle is greater than 15%.
^ Engine load is greater than 45%.
^ Engine coolant temperature is greater than 75°C (167°F).
^ Maximum spark retard is less than 15 degrees.
^ System voltage is greater than 9 volts.

Conditions for Setting the DTC
^ The PCM detects a malfunction in the integrated knock sensor diagnostic circuitry which will not allow proper diagnosis of the knock sensor circuits.
^ Above conditions are present for at least 1 second.

Action Taken When the DTC Sets
^ The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic test has been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.

Conditions for Clearing the MIL/DTC
^ The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This DTC indicates an internal PCM problem.
4. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed. Refer to PCM Replacement/Programming.