Knock sensor wiring

[Nomad1900]

Okay...I am throwing up the white flag and I need some help. Here is my story, 2003 ST1300 knock sensor fault codes. Change the sub wiring harness, still has codes. So I decided to use my manual and check the wiring. Spent hours looking through posts to make sure I use all the tips I can get. Pull out my service manual, look at the electrical diagram and it shows G/O and R/Bu as the wires I need to check. 5-46 of the manual says the left side wire is Blue-Blue to check the connection. I dont have a blue wire in my connection going to the ECU. 5-46 of the manual says the right side is R/Bu but in my harness at the knock sensor, the wire is black. While checking my black connector (picture) I found 3 wires that have continuity to ground marked with red line. So what wires at the ECU actually go to the knock sensors? My goal is to run another wire to both sides just to make sure I dont have a wiring issue. I read posts that the diagram is wrong but was fixed later and then I read the right side is actually black. Not sure where to go from here.

Thanks in advance.

 

[SMSW]

I never ran into this, I had a 2010. Pre 2008 were prone to throwing a knock sensor code (I think 26) when the ECU died. Yes, it is not the sensor or the wiring harness that is the problem, its the dang computer than makes these bikes go. There have been cases of mice chewing the wires or heat damaging the insulation and in these cases, a repair solves the problem. Absent visible evidence of damage, it is most likely that you will need a new computer. That is the bad news (they cost around $800 from Honda). The good news is that any ECU from a police bike will be cheaper - from ebay - and will work fine. Post 08 units seem to be more reliable. Speculation is that Honda fixed a problem that caused this failure.

I think you are right - the book has the sides/colors reversed. Other guys who are more knowledgeable will chime in. You can also search for 'Knock sensor error code'.

 

[Sirsilcott]

I am also having this problem I’m getting codes 25 and 26 every time I go over 4000 rpm’s for more than 30 seconds. Does anyone have a spare computer for sale cheaper than 800$?

 

[Dirtnap300]

just got myself another broken used one from fleabay.. ugh.. that was $300 wasted. So, now i have two that are throwing the error 26 code if anyone wants one... .of course.. after both the used ECUs threw the same code at the same time (about when the engine hits 4k rpm) this made me consider that the wiring may be the problem after all.... but...... dammit,, this only happens when the temps climb above 60f????? So, if i ride around in cold temps, the light stays off and the bike runs fine... FF to today.. I worked the fairings out of the way and i pulled the obviously melted plug off of the R.S. knock sensor... it surely doesn't look good but if there was a continuity problem it would happen all the time, every time... Or at least my rudimentary thinking processes feel that is correct. closer inspection of the knock sensor plug shows a non damaged wire with a in tact shielding even though the hard plastic clip had melted down like an icicle... surely not confidence inspiring.. but i am still thinking i will have to buy a NEW ECU to actually put all of this crap behind me??? well, i have my fingers crossed at least.. this is really driving me crazy.