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.
2003 Mazda 6 L4-2.3LFACTORY OEM SERVICE PROCEDURE
Knock Sensor: Testing and Inspection
KNOCK SENSOR (KS) INSPECTION
NOTE: Perform the following test only when directed.
Resistance Inspection
1. Turn the ignition switch to LOCK.
2. Disconnect the KS connector.
3. Measure the resistance between the KS terminals A and B using an ohmmeter.
- If not as specified, replace the KS.
- If the KS is okay, but 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 open or short. (Continuity check)
Open circuit
- If there is no continuity, the circuit is open. Repair or replace the harness.
- KS terminal A (harness-side) and PCM terminal 2S (harness-side)
- KS terminal B (harness-side) and PCM terminal 2P (harness-side)
Short circuit
- If there is continuity, the circuit is shorted. Repair or replace the harness.
- KS terminal A (harness-side) and power supply
- KS terminal A (harness-side) and body GND
- KS terminal B (harness-side) and power supply
- KS terminal B (harness-side) and body GND
NOTE: Perform the following test only when directed.
Resistance Inspection
1. Turn the ignition switch to LOCK.
2. Disconnect the KS connector.
3. Measure the resistance between the KS terminals A and B using an ohmmeter.
- If not as specified, replace the KS.
- If the KS is okay, but 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 open or short. (Continuity check)
Open circuit
- If there is no continuity, the circuit is open. Repair or replace the harness.
- KS terminal A (harness-side) and PCM terminal 2S (harness-side)
- KS terminal B (harness-side) and PCM terminal 2P (harness-side)
Short circuit
- If there is continuity, the circuit is shorted. Repair or replace the harness.
- KS terminal A (harness-side) and power supply
- KS terminal A (harness-side) and body GND
- KS terminal B (harness-side) and power supply
- KS terminal B (harness-side) and body GND
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.
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