P0326
DTC P0326: Knock Sensor Circuit PerformanceKnock Sensor Circuit:
CIRCUIT OPERATION
- The knock sensor (terminal No. 2) sends a signal voltage to the ECM (terminal No. 25).
- The ground terminal (terminal No. 1) is grounded with ECM (terminal No. 42).
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 ECM checks whether the output voltage changes.
DTC SET CONDITIONS
Check Condition
- 2 seconds or more have passed since the engine starting sequence was completed.
- Engine speed is higher than 3,000 r/min.
- Volumetric efficiency is 40 percent or more.
Judgement Criterion
- Knock sensor output voltage (knock sensor peak voltage in each 1/2 turn of the crankshaft) has not changed more than 0.06 volt in the last consecutive 200 periods.
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.
- ECM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
STEP 1. Check harness connector B-116 at the knock sensor for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 2.
NO : Repair or replace it. Refer to General (Electrical), Harness Connector Inspection. Then go to Step 8.
STEP 2. Check the continuity at knock sensor harness side connector B-116.
1. Disconnect the connector B-116 and measure at the harness side.
2. Check for the continuity between terminal No. 1 and ground.
- Continuity (2 ohms or less)
Q: Does continuity exist?
YES : Go to Step 5.
NO : Go to Step 3.
STEP 3. Check harness connector B-108 at ECM for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 4.
NO : Repair or replace it. Refer to General (Electrical), Harness Connector Inspection. Then go to Step 8.
STEP 4. Check for open circuit and harness damage between knock sensor connector B-116 (terminal No. 1) and ECM connector B-108 (terminal No. 42).
NOTE: Check harness after checking intermediate connector B-16. If intermediate connector is damaged, repair or replace it. Refer to General (Electrical), Harness Connector Inspection. Then go to Step 8.
Q: Is the harness wire in good condition?
YES : Replace the ECM. When the ECM is replaced, register the ID code. Refer to ID Code Registration Necessity Judgment Table
NO : Repair it. Then go to Step 8.
STEP 5. Check harness connector B-108 at ECM for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 6.
NO : Repair or replace it. Refer to General (Electrical), Harness Connector Inspection. Then go to Step 8.
STEP 6. Check for open circuit and short circuit to ground and harness damage between knock sensor connector B-116 (terminal No. 2) and ECM connector B-108 (terminal No. 25).
NOTE: Check harness after checking intermediate connector B-16. If intermediate connector is damaged, repair or replace it. Refer to General (Electrical), Harness Connector Inspection. Then go to Step 8.
Q: Is the harness wire in good condition?
YES : Go to Step 7.
NO : Repair it. Then go to Step 8.
STEP 7. Replace the knock sensor.
1. Replace the knock sensor.
2. Turn the ignition switch to the "ON" position.
3. After the DTC has been deleted, read the DTC again.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P0326 set?
YES : Replace the ECM. When the ECM is replaced, register the ID code. Refer to ID Code Registration Necessity Judgment Table
NO : Replace the knock sensor. Then go to Step 8.
STEP 8. Using scan tool MB991958, read the diagnostic trouble code (DTC).
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Erase the DTC.
4. Test drive under the following conditions:
- Engine speed: 3,000 - 5,000 r/min
- Engine load: 40 % or more
- Drive a minimum of 3 seconds after the above conditions have been met.
5. After completing the test drive, read the DTC. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P0326 set?
YES : Retry the troubleshooting.
NO : The inspection is complete.