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Honda Accord: How to Replace Knock Sensor

Ignoring a faulty knock sensor can lead to serious engine problems. Learn to detect and replace it yourself, so you can save on the professional labor costs.

By James Karuga - March 17, 2015

This article applies to the Honda Accord (1990-2002).

Timing matters in your Honda Accord's ignition system. If the air/fuel mixture ignites before the spark plug fires, this may cause damage to the pistons, piston's rings, valves, and head gasket, all of which cause the engine to lose power. Additionally with labored acceleration and rough idling, your vehicle's fuel economy will noticeably decline. You will notice this occurring by a pinging noise coming from the engine. This article will show you how to properly replace a damaged knock sensor, so you can avoid a trip to the dealership.

Materials Needed

  • New Honda Accord knock sensor
  • 27mm deep socket, ratchet, and extension
  • Flashlight (optional)

The knock sensor's purpose is to stop pre-ignition. If any pinging or engine vibrations are present, a small voltage will inform the vehicle's electronic control unit (ECU). Consequently, the ECU slows the ignition and valve timing to lower the temperature in the cylinder until the vibrations cease.

Step 1 – Remove the faulty knock sensor

The knock sensor for your Honda Accord is located next to the oil filter at the rear of the engine. You may need a flashlight to locate it. Unplug the connector, and then use the ratchet, extender, and 27mm deep socket to loosen the knock sensor. Carefully remove it by hand.

Figure 1. Location of the Accord's knock sensor.

Step 2 – Install the new knock sensor

Insert a new knock sensor in the correct location, and fasten it by hand. Use the ratchet and 27mm deep socket to tighten it to a snug fit. Then, plug the appropriate connector back onto the knock sensor plug.

Pro Tip

If the knock sensor's wire coatings are damaged, the operation of the sensor may be altered and send faulty codes to the ECU. In this case, the wires may need to be replaced as well.

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