ST1300 ECU-Knock sensor problem

Dave.David said:
My local Speed Shop routinely wipes and reprogram the ECM. They do it mostly for air fuel mixture, timing, the usual stuff but why not wonder if the wipe and reprogram would fix this problem.

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I'm little bit sceptical as Kevin from Carmo.nl "confirms" bellow:

Yes we are very experienced with the fault codes 25/26 we can also test and confirm that if you like but chances are very high that the ECU is defective.
We have tried to repair those error unfortunate after days of research we had to conclude that repairing is impossible. Replacing is your only option.

Any recommendations who can refurbish/fix here In EU, I don't know one...
 
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I'm guessing that JK may have had Shell Rotella in mind when he said that. A lot of us on here use that, including me.
 
Same problem here. I used to have the FI light come in after riding for awhile. Even while we ride in 90-100 degrees weather. I did recently changed to ethanol free fuel that is 90 octane. Bought the Honda harness. Change the bottom plug on the right side. Now the light comes on after revving it over 3900 in about 30 second. Did give me the 26 code. Also a few questions. Where is the knock sensors located? When i follow the wiring from the top it splits into 2. Has anyone bypassed the wiring just for testing? Thank You all for the write ups on this tread. Thanks to this site i saved a lot of money by changing my own clutch master slave cylinder.
 
There is an electronics guy in the Montréal area who successfully repairs ECM's from cars for local garages. He just repaired my brother-in-law's for his truck that would not start. The truck is running fine now. The charge was some around $125-150 CAD. Got me thinking about the possibility of repairing the ST1300 ECU. Curious to know if anyone has taken an ST1300 ECU to an electronics repair guy to see if they can fix them.
 
I've looked everywhere online and this is clearly an odd problem. My bike has started showing this as a 2003 model. FI light with a fault code of 26.

Now, if the knock sensors were faulty it would have been sorted by the replacement of the knock sensor - this has been done and hasn't worked.

If the wiring was faulty it would have been sorted by replacing the wiring - this has been done and hasn't worked.

You are left therefore with a faulty ECM or faulty programming. If the fault was with the ECM connector it would almost certainly show straight away and not need to wait for the bike to get warm or hit 3900 RPM. The ECM would do some self diagnostics, pick up the lack of a knock sensor and throw up the fault straight away.

So we are back to the internal ECM or the programming. Now I've worked with far more complex ECMs than this and they do go wrong - but not all the same way at around the same time. And generally, if there is a problem with the internal electronics of a computer system then all sorts of havoc is wreaked. It could be some form of internal diode or something, but again I doubt it because it wouldn't wait until the bike got warm or hit 3900 RPM and you would have to convince me that some bloke at the ECM making factory was getting all these wrong and most of these things are not made by people anymore anyway. So you'll get the sense that I am discounting the ECM hardware.

Now we are down to software. Anyone... ANYONE, that works with computers knows this goes wrong all the time. Blue screens on some windows machines, others work fine. Some crazy "patch" required on one computer and not needed on another... the list goes on. I guarantee that the highly sophisticated machine I am typing on now has a "bug" somewhere where it isn't working properly. The ECM computer by comparison is extremely simple, but is a computer programmed by humans nonetheless. This one takes in data from sensors around the machine and makes sure just the right amount of fuel is squirted in and that the spark fires at just the right time, all controlled by software. If the fuel is wrong, or the spark fires at the wrong time, the bike won't run right and you may even hear it if the timing doesn't adjust and you get "pinking or knocking". If you're varying the load by riding at different speeds and weights, and the bike is running well with reasonable fuel efficiency, then the knock sensors are almost certainly picking up the tiny "ping" that you can't hear and adjusting the timing accordingly and the ECM is fuelling and timing your machine as it should.

So what about this code then? As I said, I've worked on ECMs elsewhere and they run diagnostics all the time using a thing called BIT (Built in Testing). The ECM is listening to all the sensors and constantly asking them "everything OK?". They answer back "yep, my resistance is currently this level - I'm OK". The ECM then carries on controlling the fuel amounts and the timing.

But then it throws a code. The ECM says "The left knock sensor is not OK, I need to show the rider. I'll light this light and hold a code of 26, so that he/she can see this when they put the side stand down".

What caused this? As far as we are concerned the knock sensor is OK. After all, the bike is running well and that means the fuelling and ignition is right. If it wasn't the bike would not run well and the fuel efficiency would fall - we might hear knocking or have poor running under load. As far as we know the wiring is OK for the same reason. Same with the ECM and most likely for the internal working of the ECM. If it were a hardware fault, the bike would not run properly under certain conditions.

So, its SOFTWARE!! Blue screens, crashes, hackers etc etc.

It's the one thing that almost no biker or mechanic will really know intimately. Software secrets are kept close to the chest, and you can bet that Kiehin have never published the code they use on the ST1300 ECM. Software decides whether or not to put your bike into a "limp mode" if any sensor inputs aren't right and that can't be the case if it runs well. That means you can deduce, whatever the software is or does (and almost no-one will know this properly, just some programmer somewhere out there) the fault code 26 does not put the bike into a "get you home mode" and is not therefore limiting the power and offering a basic fuelling program. It just carries on - apparently fuelling your bike perfectly and delivering a spark at just the right time. To do this it would need to continue to get the input from the knock sensor. THE KNOCK SENSOR AND CIRCUIT IS OK!

So what is (probably) happening? Now I'm speculating. Computers like ECMs are constantly taking in inputs. If it's what it expects to get then fine, but also - if its what it "doesn't" expect to get then fine. All sensors good - carry on running, one sensor bad - let the rider know but carry on running. Try to stay with me...

We know the sensor is OK - the bike wouldn't fuel or ignite properly if it wasn't.

The problem comes when a computer "doesn't" get what it "doesn't" expect!!! With me?

1's and 0's are running all over the ECM - taking in inputs and processing through the microprocessor at the heart of the machine and then giving out outputs. If a completely unexpected 1 or 0 turns up at any time then the computer has a hell of a time processing it. Highly safety critical machines like the space station will have thing called "bit checking" to make sure this can't happen. A red little flashing light has to mean something - you can't just leave it! But what about the ST? Probably not such a big deal.

So where can these unexpected 1's or 0's come from? Well, something like an earth line for sure but that's just one thing. If the software isn't initialised properly then there will some basic assumptions the computer is making which will also be wrong. As soon as something is wrong, the computer will look to its table of faults and throw something up, and if it isn't in its table of faults it will either throw up a random fault, or as it seems in the ST1300 - fault 26 - telling you the knock sensor is out (when it isn't). So my view is that fault 26 is most likely a general fault code being thrown up by the ECM Built in Test, for a fault it doesn't really recognise. That is why it is so common and people have such a time finding out what is wrong. Took a while to get there, but that's what I think.

I would recommend:
a. Find an initialisation process (there is one on this forum) and give that a go. That makes sure the software is in the computer properly.
b. Go round the bike checking connections to "all" the ECM sensors. Give em a wiggle and check for obvious problems.
c. Check the earth lines and make sure they are all clean. This seems to happen on older bikes and earths often get a bit corroded. Everyone ignored the earth lines in every engineering job I've had. If there is a funny problem you can't solve then it always involved a bloody earth somewhere. It takes time, but it is often there somewhere.
d. Check all lines you can going to the ECM. There's loads, but again if the 1 or 0 is getting in there, its getting in from somewhere.

Once you've done that - give up. The fault is almost certainly a tiny input to the ECM which is causing it to throw up a fault 26 as a general code. It is either inside the ECM - in which case change the ECM if you can afford it - or is in one of the lines going to the ECM and you haven't been able to find it using the process above. Pay for a new ECM? change the entire wiring loom and all the sensors?... you might as well go and get a new bike.

BUT!!! There is no reason I can think of for not carrying on riding provided you can live with that little red light - and you are probably not an astronaut! If the bike is running well, then the timing and fuel are all fine so there is unlikely to be any damage done. If you're worried about it throwing a code you haven't seen, then you will almost certainly be warned about this because the bike won't work properly or go into limp mode. You'd then have to interrogate the ECM like the manual says and find out what "else" is wrong.

But I can see no reason, provided the bike runs well, that you can't just ignore the fault 26 code if you can't find what is causing it. It seems to me it is a general fault code in an imperfect bit of software programming of the bike's Built in Test (BIT) system. Your bike will not explode and will not fall to earth in a ball of flames. Fault 26 does not seem to put the bike into limp mode so you'll still get to enjoy the ST's super smooth lump thumping away under your crotch. I'm going to live with mine and see it in the same light as those little imperfections I love so much in my wife.

The problem is, I have absolutely no intention of selling my wife and explaining those little imperfections to the next owner...
 
The problem of having the fault code is that when the bike throws the knock code, it is supposed to put the bike in some sort of safe mode..Presumably retarding the spark which will cause a loss of performance and efficiency.
I don't have ocd, but that would bother me to the point of having to fix it.
.You do raise an interesting question , hardware v software , and I wonder if reflashing the ecu could possibly solve the problem.
I am sure that this isn't available through Honda, but I would think there is a way to access the program ( from a working ecu ) and reload that into the non-working ecu ?
In the 8 years I have been here, that is the only ecu problem I have seen.. and it comes up fairly frequently ...

y
 
Th
v8-7 said:
The problem of having the fault code is that when the bike throws the knock code, it is supposed to put the bike in some sort of safe mode..Presumably retarding the spark which will cause a loss of performance and efficiency.
I don't have ocd, but that would bother me to the point of having to fix it.
.You do raise an interesting question , hardware v software , and I wonder if reflashing the ecu could possibly solve the problem.
I am sure that this isn't available through Honda, but I would think there is a way to access the program ( from a working ecu ) and reload that into the non-working ecu ?
In the 8 years I have been here, that is the only ecu problem I have seen.. and it comes up fairly frequently ...

y
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I agree. So why is it the bike rides and runs fine? If its gone into "safe mode" you'd know it. Loss of power and obvious lack of fuel efficiency. Most (not all) threads I read on here seem to report the bike has not gone into the mode that retards the spark and limits power. That means either code 26 doesn't put it in safe mode - which we know it does because people report as much - or the ECM is showing a code 26 when there isn't actually a code 26 fault. The Built in Test system is just showing one. Tricky.

You shouldn't need to reflash the ECU. (Boring tech bit coming up). The program is stored in an EPROM (Erasable Programmable Read Only Memory) which is a type of memory that doesn't need electricity to keep it going (but you can only read from it, you can't write to it). This is specifically programmed by Keihin to run the ST's fuel injection system. The program on the EPROM will be tightly held but won't need to be re-flashed. Think about that first bit of activity when you turn a home computer on - this is called the BIOS. The Basic Input Output System. That BIOS is on an EPROM. That's why you can turn it off for years and the program won't dump. You don't re-flash your laptop! You don't need to re-flash your ST.

However, to run a program the computer needs a microprocessor and RAM (Random Access Memory). This is the stuff that does get erased if you turn the computer off. Some might need a bit of time to dump the 1's and 0's properly but it should dump it after a while of being turned off. The ST ECU has all of this - it has to; every computer does.

Turn the bike on, the EPROM starts outputting via the microprocessor, booting up the bike and getting everything going, checking sensors etc. It takes no time at all. Key in, start bike, rev once (well I do), side-stand up and away!! ECU kicks in proper and takes on the running of fuel and timing and I don't need to think about a thing other than the riding. All the RAM is working (or there'd be havoc), the microprocessor is working (or there'd be havoc) and the EPROM is fine (or it probably wouldn't have started or would have thrown another code - 33). At this point the Knock sensor must be working too, or there would be a fault shown.

V8-7: "In the 8 years I have been here, that is the only ecu problem I have seen.. and it comes up fairly frequently ..." - That is what really worries me. For the ECU to show the same hardware fault almost every time just doesn't obey the laws of engineering for me (there are laws? ). However, it does obey the law of software faults. If the ECM gets an "unexpected" input what does it show? All the fault codes have a purpose; there isn't a code that defines "unknown". And this is why I think it's common.

I don't know exactly how the program works, but I know that programs use tables of data and the fault codes will all be sitting in one of these tables. Fault 26 is the last one with 25 others ahead of it. Then there is this slightly odd jump in sequence where it goes to fault 33 "EEPROM fault". This smacks of a programming "fudge". Grabbing the last fault in the table when an "unknown" problem comes up is exactly the type of thing I'd expect a fudged software program to do.

So what am I saying? Well, in my view mysterious fault 26 codes are quite likely "fault unknown" codes. These can be caused by all sorts of issues. Even after market lighting might be putting an odd input up the earth line. And if there is one thing I know about ST's, they can have a lot of after market stuff on them. USB's, GPS, Radios, lighting, intercom.

I'm speculating of course, and I'm putting this on here to try and encourage people that want rid of that fault light to exhaust ALL other possibilities before changing that ECU at a £1000 a pop. New ECUs might just have a better shielding and so of course a new one would solve the problem. But the underlying "bug" is probably still there. You just don't see it anymore because it doesn't make it onto the input lines now the ECU is properly grounded.

This is my theory after years of engineering (not bikes) complex electronics. I'd love to hear from someone who put a faulty one on a good bike to see if the fault transferred - but most people test it the other way around.

So this is what I'm going to do when I get the chance:
1. Disconnect the battery and ensure the ECU has dumped all but the program in the EPROM
2. Check every wired connector that I can lay my hands on. Visually at least and manually if I can reach it.
3. Pay particular attention to the earths. Clean them anyway - your bike deserves it! These always cause "unknown" or unexpected problems.
4. Remove all after market items from the circuit. I didn't say from the bike, just isolate them all.
5. Reconnect the battery and start up the bike without touching anything.
6. Let it run to temperature. (I have no idea whether this is worth it - but it can't hurt and I haven't got a spare £1000)
7. Take the bike out and check it.

Light off: Woohoo. I was right. Start systematically reconnecting those aftermarket add-ons and see if one is setting it off.

Light on: Bugger! I give up. The ECU is almost certainly the culprit and that is another £1000. I'll just have to put up with it.

I hope that adds to the body of knowledge about this bug. Like I said, I'd be interested to hear from someone who put a "faulty" ECU on a known good bike to see if it transferred. That doesn't make it conclusive that the ECU is faulty if the fault shows, but it would mean there was nothing wrong with it if it didn't. I haven't seen anyone say they've checked the ECU like this. Most people buy a new one - fix the problem and ride off...
 
I have put a faulty ecu on my bike and it faulted right off..did not even ride it just rev'ed it over ~4k..
Wish I had ridden it so I could see if the bike actually did act differently as you suggest, it may not actually be going into limp mode..
 
In my prior post, I should have mentioned that my 2007 had around 75K miles on it and the stock ECU is fine, I bought a used ECU off someone that told me he replaced his ECU with a new one and his code was still there so we thought the replacement ecu might be ok..
 
marcusaurelius121 said:
...I've worked with far more complex ECMs than this and they do go wrong - but not all the same way at around the same time...
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My experience with electronic controllers for vehicles (specifically Volkswagen vehicles) is that when they do fail, they almost always "fail the same way".

For about 10 years, I moderated a forum for VW Phaeton owners (kind of a large, complicated Volkswagen). Owners were reporting the same problem from a failing KESSY (Keyless Entry, Start, and Stop System). Eventually one owner who owned an electronics manufacturing company in the Netherlands tore a controller down and identified the cause of the problem - it was failing MOSFETs (metal-oxide-semiconductor field-effect transistors) inside the controller.

Further investigation and data analysis by other forum members revealed that this problem correlated very strongly with vehicles that were operated in saline atmospheres - in other words, close to the sea, in places like the UK, the Netherlands, and Florida. There were never any reports of failures from owners in Switzerland or Kansas.

So, relating this experience to the F26 problem our forum members are experiencing - I think that a good first step might be to look at the geographic distribution of the failures. Is a saline atmosphere a common denominator? A good second step might be to have someone with micro-electronic skills tear down a known defective unit, and see if there is one failed component in the controller.

Michael
 
Bill Hall lived near the Atlantic coast , Skip lived in Atlanta, but the bike may have had a different history if it was bought used. Cigar Jack lived near the gulf of mexico .
BTW, I have a bad unit I would be willing to cut into, but it is potted and not sure get inside..maybe slice into the plastic 1/8 inch at a time and peel it back ?
 
v8-7 said:
Bill Hall lived near the Atlantic coast , Skip lived in Atlanta, but the bike may have had a different history if it was bought used. Cigar Jack lived near the gulf of mexico .
BTW, I have a bad unit I would be willing to cut into, but it is potted and not sure get inside..maybe slice into the plastic 1/8 inch at a time and peel it back ?
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It's a brave move but it would be hard to identify without some pretty sophisticated test equipment. There is a company in the Netherlands that does diagnosis for around 75 Euros and then will fix for around 350 Euros. It could be the same one CYYJ mentions. That would be a much better option but it's a long way away for you. https://www.carmo.nl. I'm sure there will be one in the US.

But, I'm an engineer who tries to never assume anything, but as CYYJ says, environmental factors can play a part. If there is a pattern regarding these things we should definitely try to find it. The thing with MOSFETs is that they will be in every circuit in the ECU most likely playing a part as voltage amplifiers of some kind (without a diagram I couldn't say). A saline atmosphere would be unlikely to attack just one set of MOSFETs in the same way every time. Salt doesn't seek out specific devices, though it will exploit a weakness.

v8-7 mentions at least one example where changing the ecu didn't help, but without all the detail of the prior fault finding, I couldn't conclude anything from that. That having been said, he also says he put a bad one on a good bike, and the fault showed. Still no conclusions.

I'd really like to get to the bottom of this. I reckon I can just about explain how every other part of the bike works, and I hate the thought of people wasting money on these things. Once you get to the working of software, it becomes extremely secretive and most after market companies have to "reverse engineer" by taking the inputs and outputs and then writing their own programs. We will never get to know exactly how the software works, but the ST isn't the space station - you can make some assumptions and CYYJs use of 4 wheels is a good place to start.

If the same transistors are blowing - then why? If not, then why are they all showing the same code 26? People could be paying £1000 for a £2 transistor - or worse - paying £1000 for a fault that is still floating around on the earth somewhere and confusing the fault system. I'd be really interested in hearing what the outcome is if someone sends one of these away or has the ability to test it. I don't think you'll get much from a visual inspection.

It could be my theory is nonsense. The fact that no-one has ever said they put a bad one on a good bike and it worked is telling. I just can't yet accept the same transistor every time theory just yet...but that doesn't mean I'm not wrong. Fault 26 and no limp mode has still got me stumped.
 
The fact at least one ECU is potted is a good indicator proper techniques have been used in the construction, and most potting is proof against vibrations and environmental. That doesn't rule out thermal failures l, or hidden pockets free of compound.

As to removing it, would depend on formulation. I've only had experience removing conformal resists and one I had to temporary "rubberize" with an lab oven and pull apart bits at a time.

Edit: I agree with CYYJ; my past electronics career showed me failure modes were generally "baked in" per design; weakest link and all that.
 
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marcusaurelius121 said:
There is a company in the Netherlands that does diagnosis for around 75 Euros and then will fix for around 350 Euros. It could be the same one CYYJ mentions. That would be a much better option but it's a long way away for you. https://www.carmo.nl.
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If I recall, an older thread reported carmo were able to confirm the faulty ECU but had no fix for it.



marcusaurelius121 said:
If the same transistors are blowing - then why?
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Maybe there are other commonality beside salinity? For instance, I was not aware until recently that with a weak battery, turning the bike on with a charger connected to the battery may not be such a swift idea as some chargers can deliver higher charging voltages to weak batteries, which could make their way to the electronics and which may be detrimental to the ECU. And I've done that a few times unfortunately. And so may have others?
 
Newbie 2006 Pan ST 13 owner, same problem ..FI light comes on at about 3900 RPM, seemingly only after bike has warmed up, she does seem to dip ever so slightly when the fault code kicks in, but otherwise seems to run perfectly fine....I think...as I said its a new bike to me and I have adopted the fault code, so is she running ok or is she not running ok, to me she runs perfectly.

For what its worth, and as a matter of possible interest, I purchased this bike from a late estate, which meant it had most likely not been on the road for approx a year or so, I put in an offer and I suddenly, and happily, became a Pan owner.
However she spluttered and battled along until I got her home, fault code light and all, and over a few days as time allowed I attempted some home "diagnostics", really basic stuff, believing I had a proper electrical issue, I cleaned off, lubed every single plug I could lay my hands on, drained the last bit of probable stale fuel, put in fresh fuel and injector cleaner, pulled out the fuel filter in bottom tank, at this stage I could see that "someone" had soldered the U pipe on the filter, I wondered why..., anyway I put new fuel lines in, that looked, to say the least, pathetic. In the hope that I had found the spluttering problem, all the time in the back of my mind and gutfeel, or possibly my Biker Guardian Angel telling me "Dude, this is fuel starvation....." that is when I threw out the filter, connected a straight piece of fuel line for test purposes, and wow, problem solved!!
The problem here is that someone had fitted an aftermarket fuel filter, modified the U pipe by cutting and soldering it to fit the aftermarket filter, but, in the process fitted the filter counterflow, causing the fuel starvation.
I have now put in an OEM filter, as mentioned, she runs well, but the FI light still kicks in eventually, I am not OCD either, or maybe I am to a degree, but that light still bothers me.... I have only managed to do 200 km with her with the time I have had available on my hands, and incessant rain, but I am stoked with her, what a bike, but the fault code light.... :( I am certainly not a boff, just hoping that possibly the fuel starvation confused the ECM, and its possibly a case of simply resetting the ECM...
 
fnmag said:
Welcome to the forum Ian.
Congrats on your new to you ST.
I bet you got a good deal from the estate.
Interesting that the previous owner futzed around with the fuel filter and
,modified the U pipe.
Hope it works well for you.
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Thanks for the welcome, much appreciated :) Yep I believe I got a good deal, when they surprised me with an accept, I quickly sold my Harley Sporty and grabbed the Pan :) I recently sold my big GL 1500 Wing too. But am sure the Pan will more than compensate :)I think the reason they futzed around with it was probably to try and save a few bucks, I noted the alternative filter did not seem to have a direction flow arrow, the fella probs got confused. Just wonder how long whoever it was then battled with fuel starvation, gave up and just left it like that I guess. She was in dire need of a very good service, I have tackled all that, just need to drain the coolant and put in fresh. I believe I have to remove loadsa plastics to do that..
 
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