P0328

CIRCUIT DESCRIPTION
The DTC P0328 Knock Sensor (KS) Circuit Open diagnostic monitors the activity on the knock sensor circuit. The KS is used to detect engine detonation. The KS is constructed of a piezoelectric element which generates an AC signal when vibrated. Normal engine operation will cause the KS to generate a signal of a certain known frequency. When engine knock is present, the KS frequency changes which signals the PCM to retard ignition timing. By retarding the ignition timing, the engine detonation detected should be reduced.

CONDITIONS FOR RUNNING THE DTC
The engine is running.

CONDITIONS FOR SETTING THE DTC
The KS signal detected is above 3.98 volts for more than 10 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the MIL.
^ The PCM stores the conditions which were present when the DTC set as Freeze Frame data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM turns OFF the MIL on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
^ The DTC clears after 40 consecutive warm-up cycles have occurred without a fault.
^ A DTC can be cleared by using the scan tool Clear DTC Information function.

DIAGNOSTIC AIDS
A loose KS can cause a loss of the KS signal. Check the KS for the proper torque.

An intermittent malfunction may be caused by a fault in the KS sensor electrical circuit. Inspect the wiring harness and the components for an intermittent condition. Refer to Intermittent Conditions. Intermittent Conditions

Repair any electrical circuit faults that were found. Refer to Wiring Repairs in Diagrams.

The information included in the Freeze Frame data can be useful in determining the vehicle operating conditions present when the DTC first set.

TEST DESCRIPTION

Steps 1-9:

The numbers below refer to the step numbers in the diagnostic table.
1. The Diagnostic System Check-Computers and Control Systems prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. This step checks whether the DTC P0328 is the result of a hard failure or an intermittent condition. Operating the vehicle in Check mode enhances the diagnostic capabilities of the PCM.
3. This step checks the 5 volt reference from the PCM.
4. This step checks for the knock sensor signal.
8. This step determines if the malfunction that caused DTC P0328 to set is still present. Driving the vehicle under these conditions will verify whether the fault is present. After performing the scan tool Clear DTC Information function, the DTC P0328 diagnostic can be monitored on the scan tool under the Not Ran Since Code Cleared selection in the DTC Information menu. If DTC P0328 appears in the Not Ran Since Code Cleared list, the P0328 diagnostic has not yet run. When DTC P0328 does not appear in the Not Ran Since Code Cleared list, the P0328 diagnostic has run. If the MIL is NOT illuminated and there is no Pending DTC Status in DTC Information, the P0328 diagnostic has passed. The DTCs MUST be cleared in order to view the Current Status of the Not Ran Since Code Cleared list. DO NOT forget that the Not Ran Since Code Cleared list only indicates that the test has run, not whether the test passed or failed. The DTC Information screen must be checked for Current or Pending status, in order to determine the outcome of the diagnostic test involved.