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% of a calibrated time, DTC P0327 will set.
Conditions for Running the DTC
| • | No TP sensor, VSS, CKP sensor, CMP sensor, MAF, or ECT 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%. |
| • | Engine load is greater than 45%. |
| • | Engine coolant temperature is greater than 60°C (140°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 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. |
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
Check 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 Intermittents and Poor Connections Diagnosis , and Connector Repairs Wiring Systems. |
| • | Damaged harness. |
| Inspect the wiring harness for damage. If the harness appears to be OK, observe the sensor display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the sensor display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems. |
| • | Inspect the PCM and the engine grounds for clean and secure connections. |
If the DTC is determined to be intermittent, reviewing the Fail Records can be useful in determining when the DTC was last set.
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 | Value(s) | 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 (General Description)
.
Does scan tool indicate DTC P0327 failed this ignition? | -- | |||
Using scan tool, monitor 24X crank sensor and the cam signal. Is 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 |
