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 does not use a separate KS module to monitor the system. A knock sensor module is no longer used to diagnose the knock sensor system. The circuitry is integrated into the PCM. The PCM uses the knock sensor to determine the amount of normal engine noise (noise channel) for a wide range of engine speeds and loads. The PCM compares the actual knock sensor signal to the learned 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 and 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 | -- |
