P0327

DTC P0327

CIRCUIT DESCRIPTION
The powertrain control module (PCM) monitors a knock sensor (KS) to determine if detonation is present. The KS produces an AC voltage at all engine speeds and loads. The PCM then adjusts the spark timing based on the amplitude and frequency of the KS signal. The PCM uses the KS signal to calculate the average voltage and then assigns a voltage range value. The PCM should monitor the KS signal within the assigned voltage range. This DTC will set if the KS signal is outside the assigned voltage range or the KS signal is not present.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0327 Knock Sensor (KS) Circuit Low Frequency

CONDITIONS FOR RUNNING THE DTC
- DTCs P0117, P0118, P0122, P0123, or P0125 are not set.
- The engine speed is between 2,000-3,000 RPM.
- The engine run time is more than 10 seconds.
- The engine coolant temperature (ECT) is more than 60°C (140°F).
- The manifold absolute pressure (MAP) is less than 44 kPa.
- The system voltage is more than 10 volts.

CONDITIONS FOR SETTING THE DTC
The PCM detects that the KS signal is outside the assigned voltage range or the KS signal is not present.

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

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

DIAGNOSTIC AIDS
- Inspect the KS for physical damage. A KS that is dropped or damaged may cause a DTC to set.
- Inspect the KS for proper installation. A KS that is loose or over torqued may cause a DTC to set. The KS mounting surface must be free of burrs, casting flash, and foreign material.
- The KS should be clear of hoses, brackets, and engine electrical wiring.
- For an intermittent condition, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1 - 10:

Steps 11 - 13:

The numbers below refer to the step numbers on the diagnostic table.
2. This step ensures the malfunction is present.
3. This step tests the KS for proper operation.
6. If the KS signal wire is shorted to ground or is shorted to voltage, the KS may still produce a signal.
7. If the KS low reference is shorted to ground or is shorted to voltage, the KS may still produce a signal.