P0325

Diagnostic Chart:

Engine Controls Schematics: PCM Power and Grounds:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) contains integrated Knock Sensor (KS) diagnostic circuitry. The input signal from the knock sensor is 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 sensor produces an AC signal under all engine operating conditions. During engine operation, the PCM calculates the average voltage range of the knock sensor signal. If the KS system is operating normally, the PCM should monitor the KS signal voltage varying over 0.5 volt above and below the calculated average range. If the PCM malfunctions in a manner which will not allow proper diagnosis of the KS circuit, DTC P0325 will set.

CONDITIONS FOR RUNNING THE DTC
^ The following sensor diagnostic trouble codes (DTCs) are not set:
- AIR sensor
- Vehicle Speed Sensor (VSS)
- Throttle Position (TP) sensor
- Crankshaft Position (CKP) sensor
- Mass Air Flow (MAF)
- Engine Coolant Temperature (ECT)
^ Engine speed is between 1,000 and 3,000 RPM. Throttle angle is more than 15 percent.
^ Engine load is more than 45 percent.
^ Engine coolant temperature is more than 65°C (149°F).
^ Maximum spark retard is less than 15 degrees.
^ System voltage is more than 9 volts.
^ 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 circuit.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.

The PCM will use a calculated spark retard value to minimize knock during conditions when knock is likely to occur. The calculated value will vary based on engine speed and load.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM turns the MIL OFF after three consecutive drive trips during which the diagnostic runs and passes.
^ A last test failed, or the current DTC, clears when the diagnostic runs and passes.
^ A History DTC clears after forty consecutive warm-up cycles, if no other emission related diagnostic failures are reported.
^ Use a scan tool in order to clear the MIL diagnostic trouble code.
^ Interrupting the PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Powertrain Control Module (PCM) Description, Clearing Diagnostic Trouble Codes.

DIAGNOSTIC AIDS

NOTE: Refer to Connector Test Adapter Kit J 35616-A Notice in Service Precautions.

If the problem is intermittent, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
3. 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.