P0325
Schematic:
CIRCUIT DESCRIPTION
The Powertrain Control Module (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 sensors signal. If the knock sensor system is operating normally, the PCM should monitor KS signal voltages varying over 0.5 volt more than and less than 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
^ None of the following DTCs are set.
- Throttle Position (TP) sensor
- Vehicle Speed Sensor (VSS)
- Crankshaft Position (CKP) sensor
- Mass Air Flow (MAF) sensor
- Engine Coolant Temperature (ECT) sensor
^ The engine speed is between 1000 and 3000 RPM.
^ The throttle angle is more than 15 percent.
^ The engine load is more than 45 percent.
^ The engine coolant temperature is more than 75°C (167°F).
^ The maximum spark retard is less than 15 degrees.
^ The system voltage is more than 9 volts.
ACTION TAKEN WHEN THE DTC SETS
^ The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
^ The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data.
CONDITIONS FOR CLEARING THE MIL/DTC
^ A 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
Inspect for the following conditions:
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. Refer to diagrams.
^ Damaged hamess~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. Refer to Diagrams.
^ 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
Diagnostic Chart:
The numbers below refer to the step numbers on the diagnostic table.
2. This DTC indicates an internal PCM problem.
3. If sent here from symptoms, proceed with the diagnostic table.
4. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read-only Memory (EEPROM). When the PCM is replaced, the new PCM must be reprogrammed.