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Last night I was driving home from the airport when I got my first code 23 (knock sensor). I went to check the connector to the sensor and when I applied very little presure to the connector "clip" the entire top of the sensor broke off (see pics).
I am going to assume this is a good indicator that the sensor itself has failed, but I wanted advice on how to replace this, it's REALLY not very accesible, and since its a swap, I cant remove the intake plenum without taking the entire head off. I was thinking about removing the alternator to get a little more access. Any tips are appreciated.
Questions:
1. Based on the images and how easily the sensor broke, would you assume this is simply a bad knock sensor? Or do they typically break super easily?
2. Suggestions on replacing this sensor without removing the intake plenum.
Update:
I took the car for a drive with no knock sensor and exact same result. After getting on the highway, CEL with code 23. It's worth noting that there is nothing noticeable performance wise, she is just as peppy as always. And VTEC still works even after the CEL comes on. I am feeling more and more like I just need to replace this sensor, any opinions are appreciated!
Code 23 indicates that the knock sensor circuit is malfunctioning, not that it's detecting knock so you likely just need to replace the sensor. One thing to note though is that torque does matter on knock sensors, so you'll need to do some research to figure out what torque value you need for your engine.
One thing to note though is that torque does matter on knock sensors, so you'll need to do some research to figure out what torque value you need for your engine.
Please explain this ^. Because it doesn't make sense to me and I have not heard that before.
I would check to see what or why the knock sensor was broken in half. They don't normally just fall apart. It's possible it was broken when the swap was done and just finally fell apart. I would check that the engine rocking is not hitting the sensor on something. I thought you could get to it from underneath, maybe take off the header.
Oh god there is NO WAY I will be able to fit a torque wrench back there. Ugh this one tiny sensor is going to be a nightmare. I am trying to remove the alternator just so I can have BARELY enough room, and event that is proving to be a pain in the *** so far lol...
(it IS nice to know this was likely just the sensor dying rather than actually having engine knock going on *crossing fingers*)
Question: Does anyone know what size socket I need to remove the Knock sensor? A 19mm is too small.
Please explain this ^. Because it doesn't make sense to me and I have not heard that before.
I would check to see what or why the knock sensor was broken in half. They don't normally just fall apart. It's possible it was broken when the swap was done and just finally fell apart. I would check that the engine rocking is not hitting the sensor on something. I thought you could get to it from underneath, maybe take off the header.
9 times out of 10, it will break off where the plastic connector plug is molded to the "nut" portion. Happens more often than you think
9 times out of 10, it will break off where the plastic connector plug is molded to the "nut" portion. Happens more often than you think
I meant this line:
"One thing to note though is that torque does matter on knock sensors, so you'll need to do some research to figure out what torque value you need for your engine."
Sounds like a CROME or Hondata setting, and not related to the physical sensor to me. I know they are tuned to a specific frequency, so you can't just use a random one.
Update (FIXED): This is an old thread but in case this helps anyone I thought I would post an update.
After replacing the knock sensor and still getting the same ECU Code 23, I decided to start looking into other possibilities. I thought perhaps there was a wiring issue, so with the engine running I started jiggling around wires to see if there was any reaction by the engine. When I had my hand on some wires near the distributor, suddenly I was shocked multiple times from the distributor. Upon closer inspection, I discovered the ignition rotor retaining screw was sticking out of the side of the distributor cap. Apparently this tiny retaining screw had come loose, and shredded the inside of the rotor cap, and badly damaged the rotor itself also. Anyways I replaced the cap and rotor and the problem is gone, it's annoying I spent the time and money on the knock sensor, but I'm glad to have this fixed.
TLDR: Turns out my cap and rotor needed to be replaced due to the rotor retaining screw coming loose and reeking havoc inside the rotor cap.
11-14-2019, 08:36 AM
Knock sensor questions
