2010 Mazda 5 L4-2.3LFACTORY OEM SERVICE PROCEDURE

Knock Sensor: Testing and Inspection




KNOCK SENSOR (KS) INSPECTION [L3]

Resistance Inspection

1. Disconnect the knock sensor connector.

2. Measure resistance between KS terminals A and B.

- If not within the specification, replace the KS.
- If the monitor item status/specification (reference) is not within the specification, even though the KS resistance is within the specification, perform the "Circuit Open/Short Inspection".

Resistance
- Approx. 4.87 megohms

Circuit Open/Short Inspection

Factory service manual diagram




1. Disconnect the PCM connector.

2. Inspect the following wiring harnesses for an open or short circuit. (Continuity inspection)

Open circuit

- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.

- Knock sensor terminal A and PCM terminal 2U
- Knock sensor terminal B and PCM terminal 2V

Short circuit

- If there is continuity, there is a short circuit. Repair or replace the wiring harness.

- Knock sensor terminal A and power supply
- Knock sensor terminal A and body ground
- Knock sensor terminal B and power supply
- Knock sensor terminal B and body ground

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

Shop Manual-Ready ToolsCompare Repair QuoteQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.