Circuit Description
WARNING: This page is about a different car, the 2003 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.
Each knock sensor is fitted on the right bank and left bank of the cylinder block to detect the engine knocking. Each sensor contains a piezoelectric element which generates a voltage when it becomes deformed, which occurs when the cylinder block vibrates due to the knocking. If the engine knocking occurs, the ignition timing is retarded to suppress it. See Fig 1. DTCs will set if there is no knock sensor signal to ECM with engine speed between 1700-5400 RPM. Possible causes are:
- Open or short in knock sensor circuit.
- Knock sensor loose.
- Faulty ECM.