P0325

DTC P0325: Knock Sensor Circuit

CAUTION: If DTC P0325 has been set, TCL related DTC U1120 is also set. After P0325 has been diagnosed, don't forget to erase DTC U1120.

Knock Sensor Circuit (Part 1):

Knock Sensor Circuit (Part 2):

CIRCUIT OPERATION
- The knock sensor sends a signal voltage to the PCM (terminal No. 59).

TECHNICAL DESCRIPTION
- The knock sensor converts the vibration of the cylinder block into a voltage and outputs it. If there is a malfunction of the knock sensor, the voltage output will not change.
- The PCM checks whether the voltage output changes.

DESCRIPTIONS OF MONITOR METHODS
- Knock sensor signal does not change.

MONITOR EXECUTION
- Continuous

MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable

Sensor (The sensor below is determined to be normal)
- Not applicable

DTC SET CONDITIONS

Logic Flow Chart

Logic Flow Chart:

Check Conditions
- 2 seconds or more have passed since the starting sequence was completed.
- Engine speed is higher than 2,500 r/min.
- Volumetric efficiency is 40% or more.

Judgement Criterion
- Knock sensor output voltage (knock sensor peak voltage in each 1/2 turn of the crankshaft) has not changed for 2 seconds.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 7. OBD - II Drive Cycle

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Knock sensor failed.
- Open or shorted knock sensor circuit, harness damage or connector damage.
- PCM failed.

DIAGNOSIS

STEP 1. Check harness connector B-120 at the knock sensor for damage.







Q: Is the harness connector in good condition?

YES : Go to Step 2.

NO : Repair or replace it. Then go to Step 6.

STEP 2. Check the continuity at knock sensor harness side connector B-120.







1. Disconnect the connector B-120 and measure at the harness side.







2. Check for the continuity between terminal No. 2 and ground.
- Continuity (2 ohms or less)

Q: Does continuity exist?

YES : Go to Step 3.

NO : Repair harness wire between knock sensor connector B-120 (terminal No. 2) and ground because of open circuit or harness damage. Then go to Step 6.

STEP 3. Check harness connector B-21 at PCM for damage.







Q: Is the harness connector in good condition?

YES : Go to Step 4.

NO : Repair or replace it. Then go to Step 6.

STEP 4. Check for open circuit and short circuit to ground and harness damage between knock sensor connector B-120 (terminal No. 1) and PCM connector B-21 (terminal No. 59).










Q: Is the harness wire in good condition?

YES : Go to Step 5.

NO : Repair it. Then go to Step 6.

STEP 5. Check the knock sensor.







1. Disconnect the knock sensor connector B-120.
2. Start the engine and run at idle.







3. Measure the voltage between knock sensor side connector terminal No. 1 (output) and No. 2 (ground).
4. Gradually increase the engine speed.
- The voltage increases with the increase in the engine speed.

5. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the sensor operating properly?

YES : Replace the PCM. When the PCM is replaced, register the encrypted code. Then go to Step 6.

NO : Replace the knock sensor. Then go to Step 6.

STEP 6. Test the OBD-II drive cycle.

1. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 7. OBD - II Drive Cycle
2. Check the diagnostic trouble code (DTC).

Q: Is DTC P0325 set?

YES : Retry the troubleshooting.

NO : The inspection is complete.