P0325
P0325DESCRIPTION
The knock sensor is attached to the cylinder block and senses engine knocking. A knocking vibration from the cylinder block is applied as pressure to the sensor's piezoelectric element. This vibration pressure is then converted into a voltage signal. The Engine Control Module (ECM) uses this signal to suppress knocking by retarding ignition timing.
FAILURE CONDITIONS
The ECM will set a code (Malfunction Indicator Lamp will Not turn on) if during two driving cycles the knock sensor's output voltage falls below 650 millivolts during a 4 second check when the following conditions are met:
- Starter is not engaged.
- Engine speed is above 3000 RPM.
- Engine coolant temperature is above 104°F (40°C).
- Engine load is greater than 2.5 milliseconds.
This code indicates an unexpected vibration is being read by the knock sensor or ECM under normal engine operation.
Circuit Diagram:
Test Procedure Part 1:
Test Procedure Part 2:
