KRB64 Posted March 23, 2014 Share Posted March 23, 2014 Is it as simple as it sounds? That it senses a knock? Or is it saying that the knock sensor is bad? I've searched and some of the posts say to check the sensor for cracks or swap out. Indicating that 325 code means the sensor is bad. But that won't do any good if 325 means that it's sensing a knock. It only comes on every so often. The engine develops a ticking once it warms up. At first it sounded like a loose heat shield rattle that comes and goes but I can't locate that. I'm wondering if that is what it is "sensing"? Also getting a PO420 code now in bank 1, not sure if they are connected or not? Any ideas? Thanks, Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted March 23, 2014 Share Posted March 23, 2014 (edited) The knock sensor is designed to sense knocks. This is how the ECU knows when the engine is knocking, and it responds by retarding the ignition timing. When you get a code for the sensor that means there is a problem with the sensor or the wiring to the sensor. Most of the time the sensor is bad, or the base of the sensor has corroded and is not grounded properly. P0420 code is a separate issue with dozens of different causes. Make sure you don't have any vacuum leaks or exhaust leaks. Search for Cardocs diagnostic thread for p0420, its a very informative read. Edited March 23, 2014 by Fairtax4me Quote Link to comment Share on other sites More sharing options...
KRB64 Posted March 23, 2014 Author Share Posted March 23, 2014 The knock sensor is designed to sense knocks. This is how the ECU knows when the engine is knocking, and it responds by retarding the ignition timing. When you get a code for the sensor that means there is a problem with the sensor or the wiring to the sensor. Most of the time the sensor is bad, or the base of the sensor has corroded and is not grounded properly. P0420 code is a separate issue with dozens of different causes. Make sure you don't have any vacuum leaks or exhaust leaks. Search for Cardocs diagnostic thread for p0420, its a very informative read. That clarifies it. Thanks! Quote Link to comment Share on other sites More sharing options...
Cougar Posted March 23, 2014 Share Posted March 23, 2014 The actual code is P0325. You can look up error codes on the net and even find suggestions on how to fix the trouble. The code you have there means there is a cricuit problem to the Bank 1 knock sensor. The sensor itself could be bad or the wiring between the ECU and the sensor could have a problem. Usually there is a single wire that ties the two points together. More than likely the sensor is faulty. It is a fairly common problem. 1 Quote Link to comment Share on other sites More sharing options...
KRB64 Posted March 30, 2014 Author Share Posted March 30, 2014 OK, I found the connector and it seems OK. What I can't find is the sensor itself. The Haynes manual just shows me the connector plug. Where do I look for the sensor itself? Thanks, Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted March 30, 2014 Share Posted March 30, 2014 The lo-down: http://www.ultimatesubaru.org/forum/topic/116520-knock-sensor-101-and-replacement/ Quote Link to comment Share on other sites More sharing options...
KRB64 Posted March 30, 2014 Author Share Posted March 30, 2014 Perfect, thanks! I searched but didn't get that thread. Quote Link to comment Share on other sites More sharing options...
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