Circuit Description
The knock sensor (KS) system is used in order to detect any engine detonation, or spark knock. The engine control module (ECM) will retard the spark timing based on the signals from the KS. The KS produce an AC voltage that is sent to the ECM. The amount of AC voltage produced is proportional to the amount of knock.
An operating engine produces a normal amount of engine mechanical vibration, or noise. The KS will produce an AC voltage signal from this noise. When the engine is operating, the ECM will learn the minimum and maximum amplitude of the noise the engine produces. When the ECM determines that this amplitude is above the normal operating range, DTC P0328 or P0333 will set.
Conditions for Running the DTC
| • | The engine coolant temperature (ECT) sensor is more than 40°C (104°F). |
| • | The engine speed more than 2,000 RPM. |
| • | The volumetric efficiency is more than 40 percent. |
Conditions for Setting the DTC
The KS signal is above the normal operating range.
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
| • | The KS must be torqued correctly. Refer to Knock Sensor 1 Replacement and Knock Sensor 2 Replacement . |
| • | The mounting between the sensor and engine must be free of burrs, casting flash, and foreign material. |
| • | The KS head is clear from hoses, brackets, and engine wiring. |
| • | If the KS is dropped, the KS must be replaced. |
| • | If the sensor lead is damaged in any way, the sensor must be replaced. |
| • | If there is any excessive engine mechanical noise, the DTC may set. |
| • | For an intermittent condition, refer to Intermittent Conditions . |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 |
Important: If an engine knock or excessive mechanical noise can be heard, repair the engine mechanical condition before proceeding with this diagnostic. Refer to Symptoms - Engine Mechanical in Engine Mechanical.
Does the DTC fail this ignition cycle? | -- | Go to Step 3 | Go to Diagnostic Aids |
3 |
Does the DMM display a voltage above the specified value on either circuit? | 1.0 V | Go to Step 4 | Go to Step 5 |
4 | Repair the short to voltage in the faulty circuit. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 7 | Go to Step 5 |
5 | Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 7 | Go to Step 6 |
6 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 7 | -- |
7 |
Does the DTC run and pass? | -- | Go to Step 8 | Go to Step 2 |
8 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
