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.
2007 Mazda Mazdaspeed3 L4-2.3L TurboFACTORY OEM SERVICE PROCEDURE
Knock Sensor: Testing and Inspection
KNOCK SENSOR (KS) INSPECTIONS[L3 WITH TC]
NOTE: Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See HOW TO USE THIS MANUAL.)
Resistance Inspection
1. Turn the ignition switch to the LOCK position.
2. Disconnect the KS connector.
3. Measure the resistance between KS terminals A and B using a tester.
- If not as specified, replace the KS.
- If the KS is normal, but the PID value is out of specification, perform the "Circuit Open/Short Inspection".
Specification : Approx. 4.87 megohms
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)
Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
- KS terminal A and PCM terminal 2U
- KS terminal B and PCM terminal 2V
Short circuit
- If there is continuity, there is a short circuit. Repair or replace the wiring harness.
- KS terminal A and power supply
- KS terminal A and body ground
- KS terminal B and power supply
- KS terminal B and body ground
NOTE: Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See HOW TO USE THIS MANUAL.)
Resistance Inspection
1. Turn the ignition switch to the LOCK position.
2. Disconnect the KS connector.
3. Measure the resistance between KS terminals A and B using a tester.
- If not as specified, replace the KS.
- If the KS is normal, but the PID value is out of specification, perform the "Circuit Open/Short Inspection".
Specification : Approx. 4.87 megohms
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)
Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
- KS terminal A and PCM terminal 2U
- KS terminal B and PCM terminal 2V
Short circuit
- If there is continuity, there is a short circuit. Repair or replace the wiring harness.
- KS terminal A and power supply
- KS terminal A and body ground
- KS terminal B and power supply
- KS terminal B and body ground
Factory Service Tools
Use the Manual With the Right Hardware
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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.