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 active VSS, TP sensor, ECT sensor DTCs set. |
| • | Engine coolant temperature is greater than 75°C (167°F). |
| • | Throttle angle is greater than 10%. |
| • | Engine load is greater than 55%. |
| • | Engine speed is between 1000 RPM and 5000 RPM. |
| • | Maximum system spark retard is less the 15 degrees. |
| • | System voltage is greater than 9 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 not illuminate the Malfunction Indicator Lamp (MIL). |
| • | The PCM will store conditions which were present when the DTC set as Fail Records data only. This information will not be stored as Freeze Frame data. |
Conditions for Clearing the MIL/DTC
| • | A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | DTC can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed. |
Diagnostic Aids
Check for the following conditions:
| • | Poor connection at PCM. Inspect knock sensor and PCM connectors for backed out terminals, broken locks, and improperly formed or damaged terminals. |
| • | Misrouted harness. Inspect the knock sensor harness to ensure that it is not routed too close to high voltage wires such as spark plug leads. |
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
-
Ensures that the malfunction is present.
-
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 (Symptom - Cause/Correction) in Engine Mechanical.
Does scan tool indicate DTC P0327 failed this ignition? | -- | |||
Does the scan tool indicate DTC P0327 failed this ignition? | -- | Go to Diagnostic Aids | ||
4 |
Was problem found? | -- | ||
5 |
Was problem found? | -- | ||
6 | Replace the knock sensor. Refer to Knock Sensor Replacement . Is action complete? | -- | -- | |
7 |
Does the scan tool indicate DTC P0327 failed this ign? | -- | System OK |
