2010 Mazda 3 2.5L - P0328 Knock Sensor Code and Limp Mode

Question

My dash threw a CEL and the car feels like it has no power when pulling away from stops. I am getting a persistent P0328 code for Knock Sensor 1 Circuit High Input which won't clear for more than a few minutes. I am worried about internal engine damage but there is no audible knocking or pinging under load.

Mike Reynolds · Accepted Answer

The issue was a failed internal resistor in the knock sensor itself. I removed the intake manifold (Gasket part #L3G2-13-111) and replaced the sensor with a genuine Mazda part (LF01-18-921). I torqued the new sensor to exactly 15 ft-lb as per the service manual; over-torquing is a common DIY mistake here. After clearing codes and a 20-mile drive cycle, the P0328 has not returned and full timing advance is restored.

Lina Brooks · Answer

On these MZR engines, you can check the resistance of the sensor at the X-01 connector. It should be around 560k ohms. If it's reading open or significantly higher, the piezo element inside the sensor has failed.

hd_trucker_77 · Answer

P0328 usually indicates a circuit issue rather than actual engine knock. Check the wiring harness under the intake manifold, as rodents often like to nest in there and chew the single wire going to the sensor.

Sam Holloway · Answer

Be careful when replacing this; the knock sensor is located directly under the intake manifold. You have to pull the whole manifold assembly to get a socket on it, and the torque spec is very sensitive—if you over-tighten it, it will trigger ghost codes immediately.

2010 Mazda 3 2.5L - P0328 Knock Sensor Code and Limp Mode

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