P0325

Diagnostic Chart:

Refer to Engine Controls Schematics Ignition System, Knock Sensor.

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) contains integrated Knock Sensor (KS) diagnostic circuitry. Input signals from the knock sensors are used in order to detect engine detonation, allowing the PCM to retard the Ignition Control (IC) spark timing based on the amplitude and frequency of the KS signal being received. The knock sensors produce an AC signal during all engine operating conditions. During engine operation, the PCM calculates the average voltage of each knock sensor's signal. If the knock sensor system is operating normally, the PCM should monitor the KS signal voltages that vary more 0.5 volt above and below the calculated average voltage. 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.
^ The engine speed is between 1000-5000 RPM.
^ The throttle angle is more than 15 percent.
^ The engine load is more than 40 percent.
^ The engine coolant temperature is more than 60°C (153°F).
^ The maximum spark retard is less than 15 degrees.
^ The system voltage is more than 9.0 volts.
^ The engine run time is more than 30 seconds.

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.
^ The above condition exists for at least 1 second.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the Malfunction Indicator Lamp (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 Failure Records data.
^ If the misfire is determined to be catalyst damaging, the PCM will flash the MIL.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn OFF the MIL 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.

DIAGNOSTIC AIDS
The following may cause an intermittent condition:

IMPORTANT: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

^ Poor terminal connection - Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension.
^ Damaged harness - Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault.
^ PCM and engine grounds for clean and secure connections

If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
2. This step ensures that the malfunction is present.
3. If you are sent here from Symptoms, proceed with the diagnostic table.
4. This vehicle is equipped with a PCM which uses an Electrically Erasable Programmable Read Only Memory (EEPROM). When you replace the PCM, the new PCM must be programmed.