P0327

Circuit Description
The Control Module (PCM/VCM) uses the Knock Sensor(s) (KS) in order to detect engine detonation. Ignition control (IC) spark timing is retarded based on the KS signal input when spark knock is detected. The Control Module monitors normal engine background noise during warm engine operation. It stores these noise values for comparison to the current knock sensor signal to help discriminate between normal engine noise and knock. If the amount of noise is below the minimum stored noise value, this DTC will set.

Conditions for Running the DTC
^ No active ECT sensor DTCs
^ No active TP sensor DTCs
^ The timing retard is 0 degrees or less
^ System voltage is between 10-17.1 volts
^ The ECT is more than 60°C (140°F)
^ The engine run time is more than 2 minutes
^ The knock sensor noise is less than 3 counts
^ The engine speed is between 2000-3000 RPM
^ The throttle position is more than 6%

Conditions for Setting the DTC
The difference between the actual noise value and the learned minimum noise value is less than 50 counts or more than 200 counts.

Action Taken When the DTC Sets
^ The Control Module illuminates the Malfunction Indicator Lamp (MIL) if a failure is detected during 2 consecutive key cycles.
^ The Control Module will set the DTC and records the operating conditions at the time the diagnostic fails. The Control Module stores the failure information in the scan tools Freeze Frame and/or the Failure Records.

Conditions for Clearing the MIL/DTC
^ The Control Module turns OFF the MIL after 3 consecutive drive trips when the test has Run and Passed.
^ A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22°C (40°F) from the start-up coolant temperature and the Engine Coolant Temperature is more than 70°C (158°F) during the same ignition cycle).
^ Use the scan tool Clear Information function.

Diagnostic Aids
Check for the following conditions:
^ A misrouted harness. Inspect the knock sensor harness in order to ensure that it is not routed too close to high voltage wires such as spark plug leads.
^ An improperly torqued knock sensor. Refer to Component Tightening Notice in Service Precautions. Torque the knock sensor to 19 N.m (14 lbs ft).

Review the Fail Records vehicle mileage since the diagnostic test last failed to determine how often the conditions occur that caused the DTC to set. This information may assist in diagnosing the condition.

An intermittent may be caused by any of the following conditions:
^ A poor connection
^ Rubbed through wire insulation
^ A broken wire inside the insulation

Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Refer to Intermittents and Poor Connections Diagnosis. Symptom Related Diagnostic Procedures

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. Ensures that the condition is present.
5. Ensures that the knock sensor is capable of detecting detonation. Striking the lift bracket with a non-metallic object should produce a signal that the knock sensor should detect.
7. Ensures that the 5 volt reference is near the specified value without being more than 5.2 volts.