LS430 − NEW FEATURES 17 3. Operation The knocking vibration is transmitted to the steel weight and its inertia applies pressure to the piezoelectric element. The action generates electromotive force. Steel Weight Inertia Piezoelectric Element 2 214CE08 4. Open/Short Circuit Detection Resistor During ignition ON, the open/short circuit detection resistor in the knock sensor and the resistor in the ECM keep the voltage at the terminal KNK1+ or KNK2+ constant. An IC (Integrated Circuit) in the ECM is always monitoring the voltage of the terminal KNK1+ or KNK2+.
If the open/short circuit occurs between the knock sensor and the ECM, the voltage of the terminal KNK1+ or KNK2+ will change and the ECM detects the open/short circuit and stores DTC (Diagnostic Trouble Codes) P0325. ECM 5 V Flat Type Knock Sensor KNK1+ or KNK2+ 200 k Ω 200 k Ω IC KNK1− or KNK2− Piezoelectric Element Open/Short Circuit Detection Resistor 214CE06 Service Tip In accordance with the adoption of an open/short circuit detection resistor, the inspection method for the sensor has been changed. For details, see the 2004 LEXUS LS430 Repair Manual (Pub. No. RM1048U).