Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2011 Mazda RX8 2RTR-1.3LFACTORY OEM SERVICE PROCEDURE
Knock Sensor: Testing and Inspection
KNOCK SENSOR (KS) INSPECTION [13B-MSP]
Resistance Inspection
NOTE:
- Before performing the following inspection, make sure to follow the troubleshooting flowchart. Initial Inspection and Diagnostic Overview
1. Remove the battery cover. Removal and Replacement
2. Disconnect the negative battery cable.
3. Disconnect the KS connector.
4. Measure the resistance between KS terminals A and B.
- If not within the specification, replace the KS. Service and Repair
- If the monitor item condition/specification (reference) is not within the specification, even though the KS resistance is within the specification, perform the "Circuit Open/Short Inspection".
KS No.1, No.2 resistance
- 120-280 kilohms
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Disconnect the KS connector.
3. Inspect the following wiring harnesses for open or short. (Continuity inspection)
Open circuit
- If there is no continuity in the following wiring harnesses, there is an open circuit. Repair or replace the wiring harness.
- KS No.1 terminal A and PCM terminal 2U
- KS No.1 terminal B and PCM terminal 2V
- KS No.2 terminal A and PCM terminal 2AC
- KS No.2 terminal B and PCM terminal 2Y
Short circuit
- If there is continuity in the following wiring harnesses, there is a short circuit. Repair or replace the wiring harness.
- KS No.1 terminal A and body ground
- KS No.1 terminal A and power supply
- KS No.1 terminal B and body ground
- KS No.1 terminal B and power supply
- KS No.2 terminal A and body ground
- KS No.2 terminal A and power supply
- KS No.2 terminal B and body ground
- KS No.2 terminal B and power supply
Factory Service Tools
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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.