System Description
The knock sensor (KS) system 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 learns a minimum KS noise level at idle and uses calibrated values for the rest of the engine
speed range. The ECM should monitor a normal KS signal within the noise channel. If the ECM malfunctions in a manner that will not allow proper diagnosis of the KS system, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0325 Knock Sensor (KS) Module Performance
Conditions for Running the DTC
| • | DTCs P0106, P0107, and P0108 are not set. |
| • | The manifold absolute pressure (MAP) is between 10-50 kPa depending on engine speed. |
| • | The engine speed is more than 1,600 RPM. |
| • | The engine coolant temperature (ECT) is greater than 50°C (122°F). |
| • | DTC P0325 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
| • | The ECM detects an internal malfunction in the KS circuitry that will not allow for the correct diagnosis of the KS system. |
| • | The above conditions are present for 4 seconds. |
Action Taken When the DTC Sets
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. |
| • | The driver information center, if equipped, may display a message. |
Action Taken When the DTC Sets (Non-European Emissions)
| • | The malfunction indicator lamp (MIL) will illuminate after 3 consecutive ignition cycles with a fail. |
| • | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame/Failure Records buffers. |
| • | A history DTC is stored. |
| • | The ECM will substitute a default value for intake air temperature. The scan tool will not show the defaulted value. |
Conditions for Clearing the DTC
| • | 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 non-emission related diagnostic. |
| • | Clear the DTC with a scan tool. |
Conditions for Clearing the MIL/DTC (Non-European Emissions)
| • | The MIL will turn OFF after 4 consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | A history DTC will clear after 40 consecutive warm-up cycles without a fault. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for 10 seconds. |
Diagnostic Aids
Inspect and correct any abnormal engine noise before using the diagnostic table.
Any circuitry that is suspected as causing the complaint should be thoroughly inspected for the following conditions:
| • | Poor terminal-to-wire connection |
| • | Physical damage to the wiring harness |
Step
| Action
| Yes
| No
|
1
| Did you perform the Diagnostic System Check - Engine Controls?
| Go to
Step 2
| Go to
Diagnostic System Check - Engine Controls
|
2
|
- Observe the Freeze Frame/Failure Records for this DTC.
- Turn OFF the ignition for 30 seconds.
- Start the engine.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
| Go to
Step 3
| Go to
Intermittent Conditions
|
3
| Replace the engine control module (ECM). Refer to
Engine Control Module Replacement
.
Did you complete the replacement?
| Go to
Step 4
| --
|
4
|
- Clear the DTCs with a scan tool.
- Turn OFF the ignition for 30 seconds.
- Start the engine.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
| Go to
Step 2
| Go to
Step 5
|
5
| Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?
| Go to
Diagnostic Trouble Code (DTC) List
| System OK
|
