P0327

DTC P0327

CIRCUIT DESCRIPTION
The knock sensor (KS) enables the engine control module (ECM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The KS produces an AC voltage signal that varies depending on the vibration level during engine operation. The ECM adjusts the spark timing based on the amplitude and the frequency of the KS signal. The ECM receives the KS signal through a signal circuit. The ECM supples a ground circuit to the KS through a low reference circuit. The ECM also supplies a shielded ground circuit to the KS. The ECM learns a KS noise level at idle and uses calibrated values for the rest of the RPM range. The ECM should monitor a normal KS signal within the noise channel. The circuits between the KS sensor and the ECM consists of the following circuits:
- A signal
- A low reference
- A shielded ground

If the ECM detects the KS signal outside of the noise channel, or the KS signal is not present, DTC P0327 sets.

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

CONDITIONS FOR RUNNING THE DTC
- DTCs P0106, P0107, P0108, P1106, P1107, and P0324 are not set.
- The engine coolant temperature (ECT) is more than 50°C (122°F).
- The engine speed is more than 1600 RPM.
- The manifold absolute pressure (MAP) is between 10 kPa and 50 kPa.
- DTC P0327 runs continuously once the above conditions are met.

CONDITIONS FOR SETTING THE DTC
The ECM detects an incorrect KS signal for more than 4 seconds.

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 should be free of thread sealant. The KS mounting surface should be free of burrs, casting flash, and foreign material.
- The KS must be clear of hoses, brackets, and engine electrical wiring.
- For an intermittent condition, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-2:

Steps 3-5:

Steps 6-7:

Steps 8-13:

The number below refers to the step number on the diagnostic table.
2. This step determines if the fault is current.
3. This step determines if the fault is intermittent.