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Knock Sensors

Shop OEM replacement knock sensors for Toyota, Holden, Ford, Mitsubishi, Nissan, Hyundai, Kia, BMW, Mazda and more. Matched to OEM specifications to protect your engine from detonation damage. Use the Vehicle Part Finder to confirm fitment.

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What Does a Knock Sensor Do?

The knock sensor detects high-frequency vibrations caused by pre-ignition - commonly called engine knock, pinging, or detonation. Pre-ignition occurs when the air-fuel mixture ignites before the spark plug fires, creating a sharp pressure wave inside the cylinder. The knock sensor converts these vibrations into an electrical signal and sends it to the engine control unit (ECU). The ECU responds by retarding ignition timing until the knocking stops, protecting the engine from the serious internal damage that sustained detonation causes. Without a functioning knock sensor, the ECU cannot detect pre-ignition and defaults to a fixed timing map - reducing performance and potentially allowing damaging detonation to go undetected.

Symptoms of a Failing Knock Sensor

A faulty knock sensor does not always produce the loud pinging associated with engine knock. Because the ECU retards timing as a precaution when the sensor signal is lost or incorrect, symptoms are often subtle at first. Common signs include:

  • Reduced power and sluggish acceleration - particularly under load
  • Increased fuel consumption
  • Engine hesitation when accelerating from low RPM
  • Audible pinging or knocking under hard acceleration on lower octane fuel
  • Check Engine light with codes P0325 to P0334

Because knock sensor faults cause the ECU to retard timing as a safety measure, the engine will run noticeably below its normal performance level until the sensor is replaced.

Fitment and Technical Accuracy

Knock sensors vary in resonant frequency, connector type, mounting thread size, and signal output between makes and models. A sensor with an incorrect resonant frequency will not detect knock at the right vibration frequency for your engine and may either miss real detonation events or generate false signals. Every sensor in our range is cross-referenced against OEM part numbers for an exact frequency and fitment match. Use the Vehicle Part Finder or filter by make and model to confirm the correct part for your vehicle.

Why Buy From SensorGal?

SensorGal is a 100% Australian owned family business stocking aftermarket OEM replacement knock sensors for Toyota, Holden, Ford, Mitsubishi, Nissan, Hyundai, Kia, BMW, Mazda, Subaru, Mercedes-Benz and Suzuki. With 62 sensors covering a wide range of makes and models we have the part you need in stock. Orders placed before 12 noon are dispatched same day from our Cranbourne VIC warehouse via express post. All parts carry a 1-Year Australian warranty and our no-fuss returns policy.

Frequently Asked Questions

What does a knock sensor do?

The knock sensor detects high-frequency engine vibrations caused by pre-ignition, commonly called engine knock, ping, or detonation. Pre-ignition occurs when the air-fuel mixture ignites before the spark plug fires. The sensor sends this signal to the ECU, which responds by retarding ignition timing until the knocking stops. This protects the engine from the internal damage that sustained detonation causes.

What are the symptoms of a failing knock sensor?

Because the ECU retards ignition timing as a safety measure when the knock sensor signal is lost or incorrect, symptoms are often performance-related rather than dramatic. Common signs include reduced power and sluggish acceleration particularly under load, increased fuel consumption, engine hesitation from low RPM, audible pinging under hard acceleration, and a Check Engine light with codes P0325 to P0334.

Can I drive with a faulty knock sensor?

Short distances are possible but not recommended. The ECU retards timing across the board without knock sensor feedback, leaving the engine running significantly below its designed performance level. On vehicles that use lower octane fuel or in hot conditions, the engine is also vulnerable to undetected detonation which can cause serious internal damage including piston and ring damage. Replace the sensor promptly.

Where is the knock sensor located?

The knock sensor is typically bolted directly to the engine block, often on the side or beneath the intake manifold. On V6 and V8 engines there may be two sensors, one per cylinder bank. The location varies significantly between makes and models - some are easily accessible while others require partial intake manifold removal. Check a workshop manual for your specific engine before attempting replacement.

How do I test a knock sensor?

Use an OBD2 scanner to check for codes P0325 to P0334 and review live data for ignition timing retard values higher than normal. You can also test the sensor resistance with a multimeter - most knock sensors read between 100,000 and 200,000 ohms. A sensor reading open circuit or zero ohms has failed. Some scan tools can also activate a knock simulation test to verify the sensor is responding correctly.

Does the knock sensor need to be programmed after replacement?

No programming is required for the sensor itself - it is a passive device that plugs directly in. However it is important to clear stored fault codes with an OBD2 scanner after replacement so the ECU can return to normal timing operation. On some vehicles the ECU will take several drive cycles of varied load and speed to fully relearn optimal timing after the sensor has been replaced.