P0325
2ZR-FE ENGINE CONTROL: SFI SYSTEM: P0325,P0327,P0328: Knock Sensor 1 Circuit
P0328 - Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)
DESCRIPTION
A flat type knock sensor is used. Flat type knock sensors (non-resonant type) have a structure that can detect vibrations over a wide band of frequencies: between approximately 6 kHz and 15 kHz.
Knock sensors are fitted onto the engine block to detect engine knocking.
The knock sensor contains a piezoelectric element which generates a voltage when it becomes deformed.
The voltage is generated when the engine block vibrates due to knocking. Occurrence of engine knocking can be suppressed by delaying the ignition timing.
HINT
When any of DTCs P0325, P0327 and P0328 are set, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is delayed to its maximum retardation. Fail-safe mode continues until the ignition switch is turned off.
Reference: Inspection using an oscilloscope
The correct waveform is as shown.
MONITOR DESCRIPTION
If the output voltage transmitted by the knock sensor remains low or high for more than 1 second, the ECM interprets this as a malfunction in the sensor circuit, and sets a DTC.
The monitor for DTCs P0325, P0327 and P0328 begins to run when 5 seconds have elapsed since the engine was started.
If the malfunction is not repaired successfully, DTC P0325, P0327 or P0328 is set 5 seconds after the engine is next started.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
Knock Sensor Range Check (Chattering) P0325:
Knock Sensor Range Check (Low Voltage) P0327:
Knock Sensor Range Check (High Voltage) P0328:
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT
Read freeze frame data using the 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.
PROCEDURE
1. READ VALUE USING TECHSTREAM (KNOCK FEEDBACK VALUE)
(a) Connect the Techstream to the DLC3.
(b) Start the engine.
(c) Turn the Techstream on.
(d) Warm up the engine.
(e) Enter the following menus: Powertrain / Engine and ECT / Knock Feedback Value.
(f) Read the value while driving the vehicle.
OK:
The value changes.
The knock feedback value change can be confirmed by running the engine with a high load, for example, by activating the air conditioning system and racing the engine.
NG -- INSPECT ECM (KNK1 VOLTAGE)
OK -- CHECK FOR INTERMITTENT PROBLEMS
2. INSPECT ECM (KNK1 VOLTAGE)
(a) Disconnect the knock sensor connector.
(b) Turn the ignition switch to ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
(d) Reconnect the knock sensor connector.
NG -- CHECK HARNESS AND CONNECTOR (ECM - KNOCK SENSOR)
OK -- Continue to next step.
3. INSPECT KNOCK SENSOR
(a) Remove the knock sensor.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
(c) Reinstall the knock sensor.
NG -- REPLACE KNOCK SENSOR
OK -- REPLACE ECM
4. CHECK HARNESS AND CONNECTOR (ECM - KNOCK SENSOR)
(a) Disconnect the knock sensor connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Standard Resistance (Check for Short):
(d) Reconnect the knock sensor connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - KNOCK SENSOR)
OK -- REPLACE ECM
5. CHECK FOR INTERMITTENT PROBLEMS Engine Control - SFI System - Check for Intermittent Problems
6. REPLACE ECM Removal
7. REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - KNOCK SENSOR)
8. REPLACE KNOCK SENSOR Removal