P0326 - OBD Trouble Code

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OBD-II Code P0326 is defined as a Knock Sensor 1 Circuit Range/Performance. This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles. The P0326 code means that the Engine Control Module (ECM) has detected a reference voltage from the knock sensor that has fallen outside the threshold of acceptance set by the manufacturer. If the PCM senses that the knock is severe and cannot be eliminated by retarding the spark timing, P0326 may set.

P0326 stands for knock sensor circuit performance. This means the PCM has detected a problem with the knock sensor or its circuit. Some vehicles may be equipped with two knock sensors. A 5 volt reference is supplied to the sensor and there is a signal return from the knock sensor to the PCM (powertrain control module). Code P0326 pertains to the sensor on bank 1 (the side of the engine where the #1 cylinder is located). The knock sensor tells the engine control module (PCM) that the engine has an excessive vibration resulting from an incorrect fuel and air mixture. If the PCM does not receive a signal from the knock sensor, it will set code P0326.

If the PCM determines that the knock is out of the ordinary or that the noise level is abnormally high, P0326 may set.

What causes the problem of Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor)?

• Faulty Knock Sensor
• Bad electrical connection in knock sensor circuit
• Open or shorted knock sensor harness
• Faulty engine control module (ECM)

1. Knock Sensor - The knock sensor (KS) is mounted in the engine and is used to detect spark knock. The knock sensor detects vibrations upon increase and decrease in engine rpm. Ensure its efficient functioning else can lead to the associated trouble codes.
2. Engine Coolant System - Engine cooling system provide a satisfactory temperature operating range for the engine and regulates the engine temperature to keep it just right during all operating conditions. So, if you discover it faulty then go ahead and replace or repair it as required.
3. Electronic Control Unit - Electronic Control Unit, the ECU is a name given to a device that controls one or more electrical systems in a vehicle. If it is flawed kindly repair or replace it to avoid any further trouble.

Some of the most common symptoms of Error Code P0326 include:

• Detectable knocking sound
• Spark knocking
• Pinging while acceleration
• Lack of power
• Illuminated check engine light

It is crucial to fix this error code as soon as possible. Repairs for this trouble code may include the following:

• Repair or replacing of faulty connectors or wirings associated with the knock sensor
• Replacing the knock sensor
• Plugging the knock sensor back
• Replacing the PCM

Please note that a complete diagnosis is very important on fixing this code, as nobody would want to replace a fully functioning knock sensor. So, Ensure the sensor is really the problem before replacing it.

Below are some basic steps to diagnose the trouble code P0326, though we always recommend you to have it diagnose from an experienced technician.

• If an engine knock can be heard, fix the source of the mechanical problem first then retest.
• Unplug the knock sensor and check for water or corrosion in the connector.
• If the knock sensor has a seal, verify there is no coolant from the engine block fouling the sensor. Repair as necessary.
• Turn ignition to run position with engine off. Ensure that 5 Volts are present at the KS connector.
• If resistance is normal, plug KS back in and idle the engine.
• Using a scan tool, observe KS value. Does it indicate a knock is presented at idle? If so, replace the knock sensor. If the knock sensor shows no knock at idle, then tap on the engine block while observing the knock signal. If it doesn't show a signal that corresponds with the taps, replace the knock sensor.
• If it does, verify the knock sensor wiring isn't routed next to ignition wires.

Common Mistakes When Diagnosing the P0326 Code

Common misdiagnosis while fixing trouble code P0326 includes replacement of the knock sensor when another more serious engine malfunction is to be blamed. Ensure first the knock sensor is not simply “doing its job” before condemning it to the scrap heap.