P0325

1NZ-FXE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0325: Knock Sensor 1 Circuit

DTC P0325 - Knock Sensor 1 Circuit

DTC P0327 - Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor)

DTC P0328 - Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)

DESCRIPTION

A flat type knock sensor (non-resonant type) has the structure that can detect vibrations in a wider band of the frequency from about 6 kHz to 15 kHz and has the following features.
Knock sensors are fitted on the cylinder block to detect engine knocking.
The knock sensor contains a piezoelectric element which generates voltage when it becomes deformed. The generation of the voltage occurs when the cylinder block vibrates due to the knocking. If the engine knocking occurs, in order to suppress it, the ignition timing is retarded.

HINT: If the ECM detects DTC P0325,P0327 and P0328, it enters fail-safe mode in which the corrective retarded angle value is set to its maximum value.

Reference: Inspection by using an oscilloscope.

(1) After warming up, run the engine at 2,500 rpm, and check and the waveform between terminals KNK1 and EKNK of the ECM connector.

MONITOR DESCRIPTION

The knock sensor, located on the cylinder block, detects engine knockings. When the engine knockings occur, the sensor detects vibrations in a specific frequency range. When the ECM detects the voltage in this frequency range, it retards the ignition timing to suppress the engine knockings.
The ECM also senses background engine noise with the knock sensor and uses this noise to check for faults in the sensor. If the knock sensor signal level is too low for more than 10 seconds, and if the knock sensor output voltage is out of the normal range, the ECM interprets this as a fault in the knock sensor and sets a DTC.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

P0325 (Chattering)

P0327 (Low Voltage)

P0328 (High Voltage)

WIRING DIAGRAM

INSPECTION PROCEDURE
HINT: Read freeze frame data using Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction Freeze Frame Data.

PROCEDURE

1. READ OUTPUT DTCS
(a) Connect Techstream to the DLC3.
(b) Turn the power switch ON (IG).
(c) Turn Techstream ON.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Code.
(e) Clear the DTCs DTC Check / Clear.
(f) Put the engine in inspection mode Service Precautions.
(g) Warm up the engine.
(h) Run the engine at 2,500 rpm for 10 seconds or more.
(i) Read the DTCs.
Result:

C -- CHECK FOR INTERMITTENT PROBLEMS
B -- CHECK HARNESS AND CONNECTOR (ECM - KNOCK SENSOR)
A -- Continue to next step.

2. INSPECT KNOCK SENSOR
(a) Check the knock sensor installation.
OK:
Torque: 20 N*m (204 kgf*cm, 15 ft.*lbf)
NG -- SECURELY REINSTALL SENSOR
OK -- REPLACE KNOCK SENSOR
3. CHECK HARNESS AND CONNECTOR (ECM - KNOCK SENSOR)

(a) Disconnect the E5 ECM connector.
(b) Measure the resistance between the terminals of the E5 ECM connector.
Standard resistance:

(c) Reconnect the ECM connector.
NG -- INSPECT KNOCK SENSOR
OK -- Continue to next step.

4. INSPECT ECM (KNK1 - EKNK VOLTAGE)

(a) Disconnect the E5 ECM connector.
(b) Turn the power switch ON (IG).
(c) Measure the voltage between the terminals of the E5 ECM terminals.
Standard voltage:

(d) Reconnect the ECM connector
NG -- REPLACE ECM
OK -- CHECK FOR INTERMITTENT PROBLEMS
5. INSPECT KNOCK SENSOR

(a) Remove the knock sensor.
(b) Measure the resistance between the terminals.
Standard resistance: