Circuit Description
WARNING: This page is about a different car, the 2003 Toyota Camry. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
If the ECM detects the diagnosis conditions below, it operates the fail safe function in which the corrective retard angle value is set to the maximum value.
- Detecting condition for DTC P0325 is when output voltage of the knock sensor decreases beyond a threshold (threshold varies according to an engine speed).
- Detecting condition for DTC P0327 is when output voltage of the knock sensor is 0.5 V or less.
- Detecting condition for DTC P0328 is when output voltage of the knock sensor is 4.5 V or more.
A flat type knock sensor (non-resonant type) has a structure that can detect vibrations in a wide frequency range, from about 6-15 kHz. See Fig 1. It has the following features:
- The knock sensor is fitted on the cylinder block to detect the engine knocking.
- The knock sensor contains a piezoelectric element which generates a voltage when it becomes deformed.