Circuit Description
The PCM uses a knock sensor (KS) to detect engine detonation (spark knock). The knock sensor produces an AC signal at all engine speeds and loads. The PCM makes adjustments to the spark timing based on the amplitude and frequency of the KS signal.
The PCM uses the KS signal to learn the average level of engine noise (noise channel). The PCM checks the KS system by comparing the actual KS signal to the noise channel. A normal KS signal should switch outside a voltage range above and below the noise channel. If the PCM malfunctions in a manner that will not allow proper diagnosis of the KS system, DTC P0325 will set.
Conditions for Running the DTC
| • | Engine speed is more than 600 RPM. |
| • | System voltage is between 11-18 volts. |
Conditions for Setting the DTC
The PCM detects a malfunction in the KS diagnostic circuitry that will not allow proper diagnosis of the KS system.
Action Taken When the DTC Sets
| • | The PCM will not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM will store the conditions present when the DTC set as Fail Records data. |
Conditions for Clearing the MIL/DTC
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared using the scan tool Clear DTC Information function. |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||
2 |
Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | System OK | -- |
