Knock Sensor Wire

ToroGuy

ToroGuy

Joined
Jan 26, 2006
Messages
142
Location
Spring, Texas
Bike
2003 ST1300A
STOC #
6077
I got the dreaded flashing error code light a couple of weeks ago...counted the number of flashes...looked it up in the manual and discovered the problem was the right knock sensor. I called the parts department of the four Honda dealers within a 20 mile radius of my house...surprise...nobody had a ST1300 knock sensor in stock (perhaps the subject of another thread sometime in the future). So I ordered one from an online supplier.

When I took the tupperware off and began the replacement, I discovered that most of the insulation on the wire to right knock sensor had cracked and fallen off due to heat damage from the exhaust pipes. The wire was pretty much centered between the crankcase and exhaust pipes. I went ahead and installed the new knock sensor and spliced in a new wire with heavier insulation, then wrapped the knock sensor wires on both sides with aluminum foil. No more flashing error code light.

Thought I would post this to suggest that when you have your tupperware off you may want to locate the knock sensor wires and provide a little extra heat protection (I wrapped mine with aluminum foil). My ST is an '03 with +73,000 miles. I haven't seen anyone else post this problem.
 
04 with 54,000 miles - just got the code 26 flash. Visualy inspected the wire without removing tupperware and it appears alright (my exhaust is wrapped in asbestos). Before I order the knock sensor I will be removing the tupperware and better inspect the wire. btw - the parts fische shows a special clamp to hold the wire away from the exhaust. Also - the light started flashing yesterday with temperatures close to 100, so...it may be the wire rather than the sensor.
 
Removed the tupperware (only bottom) disconnected the plug from the right knock sensor and voila - the insulation on the wire going thru the wire guide (2917703-001) was melted - obviously grounding the wire.

Put heat shrink and wrapped it with aluminum foil. Ran the bike to full warmup and then at 3900 for 30 seconds - no FI light. I hope that was all that there was to it.
 
Just came back from 100 miles at 100 degrees - NO FI LIGHT. Strike that from the squak list.

I also suspect better air flow and cooling if I leave both saddlebags home in hot weather.
 
Grrr. Mine has been giving me code 26 for a while now, but always at 4100 rpm. I think I just have to change the wiring just to be safe
 
Knock Sensor Wire another bike same problem

Happy Easter Guys

I wonder if Coreyasl had in fact had to replaced the knock sensor.
Mine ST03 is facing the same problem, code 26 and I did what Jeffrey:bow1: suggested , working on the right side of the bike, removing the Tupperware and found out a wire that is oxidized and exposed but compete and connected to the harness, a plastic outlet was rotten breaking apart.
I was able to clean it, wrapping the wire with aluminum and then applying high temperature tape, as well as, connecting now a naked terminal, to the knock sensor.
Later on I will go for a ride and push it to 4200rpm. I am afraid that i will have to replace both wire harness and sensor

take care
 
I had the same issue. Wrapped the wire and still had the problem. Checked wiring continuity, perfect. Swapped right and left sensors - still said code 26 (was expecting it to switch to code 25). New ECM - everything is fixed. Bought the ECM from a wrecked bike from e-bay for $103 shipped.
 
Dear Stgolfer

I just came back from a test ride and the problem still. I felt a little vibration at 4000 rpm then at 4200 the light came on and it loses a little power
You may be right by replacing the ECM and I will study it a little more.
If I keep the speed up to max 70 miles , I have no issues with the FI

thank you
Mickey
 
Mickey - If you want to take a ride up here, I'd be happy to switch out ECM's with you (for a test ride) to see if that solves the problem.
 
I had very similar problems with my '03. Always tripping at the exact same rpm. Switched knock sensors. Still trip the same code. Wire continuity showed good, so must be the ECM right?!?! Couldn't find a used, so ended up getting a new one.

Still the same problem. From researching here, I decided it was the wiring, despite the fact that the wiring looked perfectly fine.

I replace the wires from knock sensor to the ECM. Presto!! No more fault codes.

I would be happy to send you my ECM if you want to test it out.

Corey
 
Just thought I'd chime in with my findings. I too have had the code 26 FI fault show up. The wiring didn't look *too* bad - but (based on other peoples findings here) decided to swap that out first. Long story short, it worked - with a but...

I've only replaced a short section (where it disappears under the tank). A continuity test on the removed cable showed that it was good. The old 'wiggle' test showed otherwise though. The "but" here is that the plug (after exposure to the heat of the exhaust) had become brittle and whilst pushing the newly soldered pin back into the plug - the plug started falling to bits!

Spoke to Honda, the guy sounded unsure - but nearest thing that they've got is a sub loom - part number 32109-MCS-700. At ?50+VAT, it's not what you'd call cheap for just a 'guess'. Looking at the parts catalog though, it seems like this loom would serve both the left and right knock sensor, maybe the oil switch and another multiplug that looks very injectorish. Has anyone else replaced this loom? Ta.
 
Last edited:
ToroGuy said:
I got the dreaded flashing error code light a couple of weeks ago...counted the number of flashes...looked it up in the manual and discovered the problem was the right knock sensor. I called the parts department of the four Honda dealers within a 20 mile radius of my house...surprise...nobody had a ST1300 knock sensor in stock (perhaps the subject of another thread sometime in the future). So I ordered one from an online supplier.

When I took the tupperware off and began the replacement, I discovered that most of the insulation on the wire to right knock sensor had cracked and fallen off due to heat damage from the exhaust pipes. The wire was pretty much centered between the crankcase and exhaust pipes. I went ahead and installed the new knock sensor and spliced in a new wire with heavier insulation, then wrapped the knock sensor wires on both sides with aluminum foil. No more flashing error code light.

Thought I would post this to suggest that when you have your tupperware off you may want to locate the knock sensor wires and provide a little extra heat protection (I wrapped mine with aluminum foil). My ST is an '03 with +73,000 miles. I haven't seen anyone else post this problem.
Click to expand...
Mine is a 2003 and just had this code come up. Ordered my sensor yesterday. What was involved to change it out?
 
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