Fault code P0325 – a step-by-step guide to diagnosing and fixing it

DTC P0325 generally means that knock sensor 1 on cylinder bank 1 is malfunctioning. This device is used to detect when the engine is knocking, and thereby delivering less power. This code is triggered when the car's ECUdoesnt receive a signal from the sensor or there is something wrong with the sensor readings. In order to identify this fault, the engine should be running at the right operating temperature and at a speed between 1,600 and 5,000 rpm.

• The knock sensor could be defective due to damage to or leaks in the housing, extreme temperatures, vibrations, and so on. This is arguably the most common cause of the fault.
• The connection could be affected by a loose cable or electromagnetic interference. Interference occurs when the device is installed too close to high-voltage ignition components.
• A wiring fault such as a short. This can occur due to mechanical, thermal or chemical damage, resulting in cracks, deformation, melting or fraying. The circuit may also be affected by corrosion.
• An error could also be caused by a loose fastener or improper installation. The device should be securely attached to the power unit.

• Activation of the check engine light
• A loss of power
• Engine hesitation
• Reduced acceleration
• A decrease in fuel efficiency
• Strange noises coming from the engine compartment during acceleration
• Knocking

• Connect an OBD2 scan tool to the vehicle via the data link connector and check whether any other diagnostic codes are present. This should help you to identify any underlying problems. Similar DTCs include P0327 and P0328, referring to the voltage output.
• Measure the resistance of the knock sensor using a multimeter and compare this to the factory specifications. This should be indicated in the vehicles repair manual. If the readings are abnormal or there are visible signs of damage, you may need to replace the device. Check whether the sensor has been installed properly, it may need to be reattached or fastened.
• Make sure this issue isnt being caused by a wiring fault. Replace the wires or cables connected to the component if they are frayed or melted. Corroded contacts should be cleaned and treated with specialised products.
• If you decide to replace the knock component, it is also recommended to replace the knock harness at the same time.