My mazda 2 had engine light on. Diagnostic showed these 2 codes. Any ideas? Thanks

 

P0328 is a Knock Sensor fault code..

U0401 is a communication fault, & usually aren't anything to worry about.



DTC P0328:00
KS circuit high input

DETECTION CONDITION
• If the input voltage is more than 3.75 V, the PCM determines that the KS circuit has a malfunction.
Diagnostic support note
• This is a continuous monitor (CCM).
• The MIL illuminates if the PCM detects the above malfunction condition during the first drive cycle.
• FREEZE FRAME DATA (Mode 2)/Snapshot data is available.
• The DTC is stored in the PCM memory.

POSSIBLE CAUSE
•KS connector or terminals malfunction
• KS malfunction
• PCM connector or terminals malfunction
• Short to power supply in wiring harness between KS terminal A and PCM terminal 2AN
• Open circuit in wiring harness between KS terminal A and PCM terminal 2AN
• PCM malfunction

 

Thank you for that info, she's that mean I just need to replace the knock sensor?

Thanks

 

No, not necessarily, it could be a faulty sensor, or faulty wiring or even a faulty ECU/PCM.

It will require complete diagnostics to find the actual fault.

You can fit a new knock sensor & hope that's the fix, you might be lucky, you might not.

 

Hi, I have a mazda2 and have owned it since 2008 (new) and just reached 100k km. Last week I encountered the below fault, I tried to clear however it appeared again.
I removed the cable going to the knock sensor and with ignition on there was 7v.

DTC P0328:00
KS circuit high input

I checked the voltage as indicated above and found that I have 5v. Can anyone explain to me what is the KS circuit?

• If the input voltage is more than 3.75 V, the PCM determines that the KS circuit has a malfunction.

 

I replaced the sensor with a genuine one which costed around €110 and problem seemed to be fixed.

Had to remove fuel rail (did not disconnect the fuel pipe to the rail), throttle body, intake manifold and then had access to the sensor.

Job took around 2hrs