Introduction to On Board Diagnostics (II)

Fundamentals of PowertrainControl strategies & OBD IIDiagnosticsKnock Sensor ( DTCs 325-334):334): Knock sensor diagnostics areperformed for deterioration of piezoelectric or magneto restrictivecharacteristics. In case of electrical circuit malfunction fault t code 325 isassigned. If the sensor 1 circuit is indicating out of range readingfault code 326 is assigned. If the sensor 1 circuit is indicating very lowreading fault code 327 is assigned. If the sensor 1 circuit is indicatingvery high reading fault code 328 is assigned. Knocking is detected ected bythe oscillation frequency of the piezoelectric device or the voltagedeveloped by themagnetorestrictive device when knocking occurs. Ifthe sensor 1 circuit is indicating intermittent faulty reading g fault code329 is assigned.If the sensor 2 circuit is indicating same faults as listed above, fault codes330-3334 3334 are assigned to the respective faults. Knock sensor diagnosticsare described in detail in a later section.