Circuit Description
The PCM contains integrated Knock Sensor (KS) diagnostic circuitry. An 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 of the knock sensor signal. If the knock sensor system is operating normally, the PCM will see KS signal voltage vary above and below the calculated voltage average. If the PCM detects KS input signal equal to the KS average voltage over 95 percent of a calibrated time, DTC P0327 will set.
Conditions for Running the DTC
| • | No TP, CMP, CKP, ECT sensor, or VSS DTCs are set. |
| • | Engine speed is between 1000 and 5000 RPM. |
| • | The engine has been running for a minimum of 30 seconds. |
| • | Throttle angle is greater than 15 percent. |
| • | Engine load is greater than 40 percent. |
| • | Engine coolant temperature is greater than 60°C (153°F). |
| • | Maximum spark retard is less than 15 degrees. |
| • | System voltage is greater than 9.0 volts. |
Conditions for Setting the DTC
The PCM detects a Knock Sensor signal voltage within the calculated average voltage range for at least 10 seconds.
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/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has 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:
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
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.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | 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. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Test Description
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Ensures that the malfunction is present.
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If both the 24X Crank Sensor and the Cam signal are not present the KS signal will stop updating and may set DTC P0327. The ignition positive voltage supply and the ground circuits need to be diagnosed using the DTC P0336.
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If sent here from symptoms, proceed with the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On Board Diagnostic (OBD) System Check performed? | -- | ||
|
Important: : If a mechanical engine knock can be heard, repair the engine mechanical
problem before proceeding with this diagnostic. Refer to
Engine Noise Diagnosis
in Engine Mechanical.
Does scan tool indicate DTC P0327 failed this ignition? | -- | Go to Diagnostic Aids | ||
Using scan tool, monitor 24X crank sensor and the cam signal. Is the 24X Signal and Cam Signal present? | -- | |||
Does the scan tool indicate DTC P0327 failed this ignition? | -- | Go to Diagnostic Aids | ||
5 |
Was problem found? | -- | ||
6 |
Was problem found? | -- | ||
7 | Replace the knock sensor. Refer to Knock Sensor Replacement . Is the action complete? | -- | -- | |
8 |
Does the scan tool indicate DTC P0327 failed this ignition? | -- | System OK |
