P0325 – Knock sensor (KS) 1 , bank 1 -circuit malfunction
Last Updated 2016-09-06
ASE Master Tech
|Code||Fault Location||Probable Cause|
|P0325|| Knock sensor (KS) 1 , bank 1 -circuit malfunction |
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|Wiring, poor connection, KS|
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Table of Contents
- What Does Code P0325 Mean?
- What are the common causes of code P0325 ?
- What are the symptoms of code P0325 ?
- How do you troubleshoot code P0325 ?
- Codes Related to P0325
- Get Help with P0325
What Does Code P0325 Mean?
The knock sensor (KS) is mounted in the engine and is used to detect spark knock. When there is spark knock or pinging, the sensor produces a voltage signal that is sent to PCM. The PCM will then retard ignition timing to protect the engine.
Inside, the knock sensor is a piezoelectric crystal. This crystal is used to produce AC voltage under vibration. The knock sensor is a form of transducer, which is a device that converts changes in physical quantity into an electrical signal. In other words, a knock sensor does not receive a reference voltage from the PCM – it creates its own.
There are two basic types of knock sensors: the style used in older vehicles and the resonant design used in modern vehicles.
Cross section of a typical knock sensor
P0325 stands for knock sensor circuit malfunction. This means the PCM has detected a problem with the knock sensor or its circuit. Some vehicles may be equipped with two knock sensors. Code P0325 pertains to the sensor on bank 1 (the side of the engine where the #1 cylinder is located).
What are the common causes of code P0325 ?
To sum things up, the common causes for code P0325 are as follows:
- Failed knock sensor
- Fault in the knock sensor circuit
- Failed PCM
What are the symptoms of code P0325 ?
You may notice a lack of power, hesitation and/or pinging. In some cases, however, an illuminated check engine light will be the only symptom.
How do you troubleshoot code P0325 ?
The following steps will help you troubleshoot a P0325 code:
- Perform a visual inspection of the sensor and connection.
Many problems can easily be found in the harness and connectors. So, begin your diagnosis by visually inspecting the sensor and its connection.
- Perform a basic test of the knock sensor
Note that this test will only work on old style knock sensors. Connect a timing light to the vehicle and start the engine. Allow the engine to warm up and aim the timing light toward the timing marks on the harmonic balancer. Locate the knock sensor and tap on an engine location near the sensor (do not directly strike the sensor). If the sensor is working correctly, you should see the timing begin to retard. If not, you have a problem with the sensor or its circuit. Hint: this test can also be performed by monitoring the ignition timing on a scan tool, instead of using a timing light.
- Test the sensor output
If your vehicle fails the basic test listed above, it’s time to determine what part of the sensor circuit is to blame. To test an old-style knock sensor, connect a digital multimeter set to AC voltage between the knock sensor output signal wire and a good ground. Then once again, tap on an engine location near the sensor. You should see an AC voltage reading on your digital multimeter. If not, the sensor is bad and should be replaced.
An old-style knock sensor
Testing an old-style knock sensor
To test a vehicle with a resonant style sensor, you’ll connect your digital multimeter the same way as you would for a Weidman style sensor. But, instead of tapping on the engine block, you’ll start by removing the fuel pump relay to prevent the engine from starting. Crank the engine, put the vehicle in gear and keep your foot on the brake. Accelerate a little; as the vehicle is starved for fuel it will begin to ping and you should see an AC voltage output. If not, the knock sensor is bad and should be replaced.
A resonant style knock sensor
- Check the circuit
If the knock sensor checks out OK, but you still have P0325 code illuminated, you’ll need to check the sensor circuit. Using a digital multimeter set to the ohms, connect one side of the meter to the harness side of the knock sensor connector and the other to the knock sensor input pin on the PCM. This tests for continuity between the sensor and PCM. If your meter reads OL, there is an open somewhere in the circuit that must be repaired. If not, the PCM is likely the problem and should be replaced.
Typical old-style knock sensor circuit
While old-style knock sensors ground through the sensor itself, resonant style sensors typically have a separate ground circuit. In this case, you’ll want to use a digital multimeter to ensure there is a good ground before condemning the PCM. Start by consulting the wiring diagram for your vehicle from All DATA DIY to determine which pin on the connector is power and which is ground. Next, connect the red multimeter lead to the battery positive terminal and the black lead to ground. You should see a reading of about 12 volts indicating a good ground. If not, you’ll need to consult the ground side of the wiring diagram to find where the circuit fault lies.
Typical resonant knock sensor circuit
Codes Related to P0325
- DTC P0324: Knock Sensor (KS) Module Performance
- DTC P0326: Knock Sensor (KS) Performance
- DTC P0327: Knock Sensor (KS) Circuit Low Voltage Bank 1
- DTC P0328: Knock Sensor (KS) Circuit High Voltage Bank 1
- DTC P0330: Knock Sensor (KS) Circuit Bank 2
- DTC P0332: Knock Sensor (KS) Circuit Low Voltage Bank 2
- DTC P0333: Knock Sensor (KS) Circuit High Voltage Bank 2
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I need an assistance, my Camry 1999 model is showing error message p0325 on OBD2 scanner and also other codes p0500, p0753,p0758. Just to know if they are related and what to do. Thank you
I got Honda CRV 2005 model.
It showing me PO325PND, PO325CNF, Knock Sensor 1, MOD $09, Knock Sensor 1 Circuit (Bank1), Engine or Signal Sensor, Right Front Wheel Speed sensor Malfunction.
Is there a serious problem? what is the impact if i do not repair it soon?
Hey there. Check that the knock sensor connector is fully seated. The knock sensor is near the starter, but I’m not sure how easy it is to get at it.
Hello everyone!i have a toyota caldina 1AZ-FSE engine .this have a trouble code p0325 problem.i replaced ecm & knock sensor but when i am driving at 82C , my car is always showed p0325 malfunction . Can you help me and how to test knock sensor a good or bad .
We do not have the Caldina here in the states, but the RAV4 uses the 1AZ-FSE engine, so I will use it for reference. The knock sensor contains a piezoelectric element which generates a voltage when it becomes deformed. This happens when the cylinder block vibrates due to knocking. If engine knocking occurs, ignition timing will be suppressed to prevent it. If you’ve already replaced the sensor and the ECM, I would check the wiring between the two. To do this, remove the connector from the PCM and knock sensor. Use a digital multimeter set to ohms and touch one lead to the knock sensor signal wire to the PCM and the other to knock sensor pin at the PCM. If the meter reads out of limits (OL), there is an open circuit. You’ll need to consult the factory repair information to trace the problem. This appears to be a single wire sensor, which grounds through the body.
Can knock sensor malfunction cause gear shift problems? My kluger sometimes fails to shift to gear 4 when the engine check light turns on.
I looked online and the Kluger appears to be the same thing as the Toyota Highlander here in the states. My guess is that what you are experiencing is the vehicle going into fail-safe mode. In the case of your vehicle, the ECM will delay the ignition timing to maximum retardation. You may interpret this as problem with the transmission shifting. With this particular code, it doesn’t look like the ECM would prevent shift solenoid operation in fail safe mode. Hope this helps.