HELP CEL 23 - Knock Sensor?

We may earn a small commission from affiliate links and paid advertisements. Terms


Junior Member
Have a B16A JDM with Type R head in a 90 hatch. Has been running great for about a year and now is throwing a code - 2 long blinks and 3 quick blinks, so I think that means 23.. when I looked it up it refers to the Knock Sensor... I have tried reseting the ECU and it will still pop up after a few minutes of driving.

What should I do or check? Have always used 87 oct. gas..

Okay, I have tried adding an additive to the fuel and went to a full tank of 89 Oct gas and reset the ECU.. The light still comes on with a 2 blink and 3 blink -fast, so I am guessing it is still the knock sensor...

Any thoughts? as this is the first time this has happened in over 3 years of flawless use
using 87 octane is a no no with these motors ... use premium fuel only, if not.. it will cause a knock..

i'm guessing the sensor may need to be replaced since you've used 87 only... probably wore out the sensor from all the knock you had.. again, thats a guess... the plug could have just came loose, have you checked it.. on the backside of the block above the oil filter
i have a 93 ex with a jdm b16a, im using the small box p30 and im gettin the same code knock sensor. I've always used 93 octane.
so check the sensor, it's not rocket science. if it is unplugged (which can happen with age, plastics crack and plugs work their way off) then fix the plug, if the sensor it self is cracked obviously replace it. if it looks good though, then unplug the ecu (after disconnecting the battery) and use a multimeter to check for continuity in that wire. if it's good, replace the sensor with a known good sensor.

one other thing to note, that wire is shielded on stock vehicles, and usually not on swaps. honda shields it from RFI and EMI because that circuit is very sensitive, if you recently added some new stereo, alarm, or *gasp* neon lights.... that may be causing your interferance problem.
Last edited: