Troubleshooting
DTC P0325 KNOCK SENSOR 1 CIRCUIT (BANK 1 OR SINGLE SENSOR)CIRCUIT DESCRIPTION
DTC Detection Condition:
The each knock sensor fitted on the right bank and left bank of the cylinder block is used to detect the engine knocking.
Each knock sensor contains a piezoelectric element which generates voltage when it becomes deformed. Generation of the voltage occurs when the cylinder block vibrates due to knocking. If engine knocking occurs, the ignition timing is retarded in order to suppress the knocking.
HINT:
- Bank 1 refers to the bank that includes cylinder No.1.
- Bank 2 refers to the bank that does not include cylinder No.1.
Reference: Inspection using the oscilloscope.
a. Check the waveform between terminals KNK1 and KN1(2 of the ECM connector and body ground at 4,000 rpm.
Standard: Refer to the illustration.
b. Spread the time on the horizontal axis and confirm that period of the wave is 0.123 msec (normal mode vibration frequency of knock sensor: 8.1 kHz).
If the normal mode vibration frequency is not 8.1 kHz, the sensor is malfunctioning.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Conditions:
Typical Malfunction Thresholds:
The knock sensor detects spark knock. When spark knock occurs, the sensor picks-up vibrates in a specific frequency range. When the ECM detects voltage in this frequency range, it retards the ignition timing to suppress the spark knock.
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.
Wiring Diagram:
Step 1:
Step 2:
Step 3:
INSPECTION PROCEDURE
HINT:
- DTC P0325 is for the left bank knock sensor circuit.
- DTC P0330 is for the right bank knock sensor circuit.
- Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.