P0325

DTC P0325:

Knock Sensor Wiring Schematic:

CIRCUIT DESCRIPTION
The Knock Sensor (KS) is used to detect engine detonation. The Powertrain Control Module (PCM) receives the knock sensor signal and will retard Ignition Control (IC) timing until knock is not detected.

The circuitry within the KS will drop approximately half of the 5 volts applied to the sensor on CKT 496. When engine detonation occurs, the sensor produces an AC signal which rides on the 2.5 volt DC signal. The voltage amplitude and frequency is dependent upon the knock level emitted from the engine combustion process.

DIAGNOSTIC TROUBLE CODE (DTC) P0325 WILL SET WHEN
The PCM detects above 3.56 volts or below 1.52 volts for 20 seconds.

ACTION TAKEN (PCM WILL DEFAULT TO)
The Malfunction Indicator Lamp (MIL) will become illuminated. Knock retard will be fixed at 15 degrees.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. If the conditions for DTC P0325, as described above, are being met, the Tech 1 scan tool will always indicate "Yes" when the knock signal position is selected. If an audible knock is heard from the engine, repair the internal engine problem, as normally no knock should be detected at idle.
2. The PCM applies a 5 volt signal to the sensor on CKT496.

DIAGNOSTIC AIDS
Check CKT 496 for an intermittent open or short to ground or short to voltage. Also, check for proper installation of KS module.
If the knock sensor CKT 496 is routed too close to secondary ignition wires, it may induce a voltage and cause a false knock signal.
See "Detonation/Spark Knock," under "Diagnosis by Symptom". Detonation/Spark Knock/Pings