MIL On With DTC P0325?
If you are lucky it will just be a loose connector.Check the Knock Sensor
Currently Applies To: ’06–09 Accord, ’06–09 Civic
Si, ’06–09 CR-V, and ’06–09 Element
Troubleshooting a vehicle with the MIL on and DTC
P0325 (knock sensor circuit malfunction)? Don’t just
rush off and replace the knock sensor. The knock
sensor connector might be the real culprit. Some of
these connectors might not have been properly
plugged in during assembly, which could lead to an
intermittent DTC P0325.
To fix this problem, give the knock sensor connector
a gentle tug. If the connector comes right off, plug it
in and make sure it’s secure. Then clear the DTC,
and retest. If the DTC doesn’t come back, you’re
done. But if it does—or the connector was secure to
begin with—then continue with normal
I just changed my knock sensor. Despite the Youtube videos (which mainly seem to be about the CR-V), you cannot access the sensor from above. As per the service manual, you must remove the plastic air dam from the bottom of the car and reach up to the sensor. This is easier said than done. I found getting to the sensor with my big hands a RRPITA.
I suggest that anyone with a high-mileage engine who has to replace their starter (which requires removing the intake manifold) should consider replacing the knock sensor at the same time, even though it costs about $60. There is no better time than when the intake manifold is off to swap out the sensor, and it's the only time you would be able to clean the contact on the connector.
Oh, and after replacing the sensor, I reset the error code three or four times, and it kept coming back on. I was resigned to having the engine light on forever and checking every week or so to make sure a new code hadn't popped up. But after a couple of hours of driving, the light went out. Go figure.