ST1300 ECU-Knock sensor problem
- Thread starter Shaw
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I am new to the group. I have a 2004 ST1300,and am having the F1 light with a code 25 Left side sensor). I have replaced the sensor but still have the F1 light when held at or above 4000 rpm for 10 seconds. The wiring is good between the ECM and sensor and it is the blue wire with the red stripe like the shop manual shows. I have also read tons of comments about this in the forum and am seeing mixed results when the ECM is replaced. Don't want to throw money at the ECM if that won't help. The light came on about 8 yrs ago and after changing gas the problem has not returned till about the last few weeks. Just wondering if it is (like many have suggested) a heat related problem. It has been 95+ F degrees here and wondering if that might be something i could address by in-casing the ECM in styrofoam or some other material to keep it cool . After I replaced the sensor we cranked the bike up and let it come up to temp. We held the rpms up to about 5000 for 10 seconds and the light did not come on. I road the bile for about 30 min and never tried to make to light come on. After a while i decided to leave it in 3rd gear and hold it over 4000 for 10 seconds and the light again came on. Now that I know the secsor i removed was ok i am thinking about replacing the right side sensor and see if i get the F1 light. A question here for the experienced F1 light people. If I unplug the right side sensor in an attempt to pull a F1 light and a code. Is it possible to get a code 25 and a code 26 at the same time? Thanks for any help in this very frustrating problem...UPDATED Put a diffrent sensor on the right side and still pulled a code 25....I need help....I can't even find an new ECM on the web
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The engine is not pinging. I can trigger the light under no load. I can crank it let it come to temp and rev it to 4000 rpms and the light will come on. Thanks for the reply
I have been thru this, you will have to replace the ECU or ECM. i.e. the control module for the engine.
I've just had and fixed the same issue. All wiring checked out ok and, based on extensive reading here, I decided not to change the sensors themselves as they were very unlikely to be bad. I saw the police ECM on eBay and asked the vendor if he knew what the differences were. He replied that I should get the exact replacement to be sure everything was the same. (he could easily have said - it 'should work' and try to sell it to me. So I appreciate his honest response).
I ended up buying a used one from a member here, put it in and no F1 light. This has been most, though not everyone's, experience.
I would recommend you do the same and you will probably fix the issue.
FWIW, I would guess you had a real problem until changing the fuel but eventually the ECM failed and then always lit the F1.
I also believe that the codes 'stack'. ie: if both sensors are bad, one code will show and then, when fixed, the other will show.
Cheers
Derek
I ended up buying a used one from a member here, put it in and no F1 light. This has been most, though not everyone's, experience.
I would recommend you do the same and you will probably fix the issue.
FWIW, I would guess you had a real problem until changing the fuel but eventually the ECM failed and then always lit the F1.
I also believe that the codes 'stack'. ie: if both sensors are bad, one code will show and then, when fixed, the other will show.
Cheers
Derek
My problem went away once mother nature cooled off a bit. The last few weeks the tmeperature has picked up but he code hasn't returned. Okay... problem comes and problem goes.
UPDATE Knock Sensor problem solved. The spark plug was causing the issue. We changed the plugs and could not make the F1 light come on. There was nothing visibly wrong with the plug but one on the left side was causing the knock sensor problem. So glad too we were about to throw $800.00 at a ECM and fixed it with a $8.00 spark plug. Thanks for all the help.
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By any chance, did you swap the left and right plugs, to check if the "bad" plug could also trigger the Code on the other side?
Andrew Shadow
Site Supporter
The spark plug being the problem seems a little confusing to me so I need some help to understand it.
Correcting the problem, and eliminating the setting of the code, by replacing the spark plug suggests that the knock detection system and the ECU are not defective and are in proper working order. If they are in proper working order then this means that the system was functioning as designed and that the code was actually being triggered because the system was in fact detecting an excessive amount of knocking beyond its ability to control.
Assuming that there is no defect in the system that is erroneously causing a code to be set, the ECU normally will not illuminate the FI light and/or set a code unless the knocking that it is detecting exceeds its ability to compensate for. This means that the amount of knocking that was being detected could not be brought under control by retarding the timing by the maximum amount that the ECU is capable of.
However, Truman wrote that he did not have any knocking. He also wrote that he could trigger the code under a no load condition. Unless I misunderstand how this system operates on the ST1300 and again assuming that the system is functioning correctly, the only way that I can see a defective spark plug being able to trigger this code under these conditions is if it is causing significant knocking. The knocking would have to be beyond the ECU's ability to bring it back within the acceptable range, by retarding the timing, before this code would be triggered. This would have to be a significant amount of knocking that would result in a significant amount of timing retardation. I can't imagine this occurring under a no load condition. I also can't imagine that it would not be noticed in reduced power output and without being audible as well.
Based on the assumptions that the system is functioning correctly, that there was no engine knock or performance loss, and that the spark plug was the cause of the code being set my question is this- what condition is a defective spark plug capable of causing that would trigger this code to be set if it is not as a result of excessive engine knocking?
Correcting the problem, and eliminating the setting of the code, by replacing the spark plug suggests that the knock detection system and the ECU are not defective and are in proper working order. If they are in proper working order then this means that the system was functioning as designed and that the code was actually being triggered because the system was in fact detecting an excessive amount of knocking beyond its ability to control.
Assuming that there is no defect in the system that is erroneously causing a code to be set, the ECU normally will not illuminate the FI light and/or set a code unless the knocking that it is detecting exceeds its ability to compensate for. This means that the amount of knocking that was being detected could not be brought under control by retarding the timing by the maximum amount that the ECU is capable of.
However, Truman wrote that he did not have any knocking. He also wrote that he could trigger the code under a no load condition. Unless I misunderstand how this system operates on the ST1300 and again assuming that the system is functioning correctly, the only way that I can see a defective spark plug being able to trigger this code under these conditions is if it is causing significant knocking. The knocking would have to be beyond the ECU's ability to bring it back within the acceptable range, by retarding the timing, before this code would be triggered. This would have to be a significant amount of knocking that would result in a significant amount of timing retardation. I can't imagine this occurring under a no load condition. I also can't imagine that it would not be noticed in reduced power output and without being audible as well.
Based on the assumptions that the system is functioning correctly, that there was no engine knock or performance loss, and that the spark plug was the cause of the code being set my question is this- what condition is a defective spark plug capable of causing that would trigger this code to be set if it is not as a result of excessive engine knocking?
Another Update. The plug model in NGK 3486-plug # cr7eh-9. We road the bike today and could not make the light come on for about the first hour in the 80 degree outside temperature range. After about 50 miles the F1 light was back on and it was 90+ degrees. It has been extremely hot here and got up to about 97 today during the ride. The F1 light only comes on at 4000 rpms. I can hold it at 5 , 6 or 7000 rpms and the light won't come on. Think this thing is gona be heat related...we will keep this updated
We swapped the knock sensor and cant get a code 26 which is the right side knock sensor. We can only get a code 25. Ordered a new set of plugs today. the ones put in yesterday had about 20000 miles on them. Still kinda weird that after the plugs were swapped the problem went away for a while.
Andrew Shadow
Site Supporter
I was afraid the problem might reappear. The conditions that you described, especially the 4,000 RPM threshold, sounds very similar to what many other people who have had the same problem have described. In most cases that I have read about the end solution often is a replacement ECU. Hopefully you will have better luck and a different outcome.
Happy for you that it was not ECM, and I believe yours was a classic case of "begin at the basics", the thought of having to replace an ECM is nauseating to say the least, my opinion is that major Honda electronics do not usually fail....but just my thoughts, I had previously mentioned that I purchased my ,07 ST 13 blindly, was initially horrified that I was most likely in for a new ECM, as the ST was misfiring and generally running poorly, (the ECM replacement suggestion confirmed by a Honda Dealership), after much scratching about in the eves after work only to find that previous owner (deceased) had modified an aftermarket fuel filter in tank and fitted counter flow. (No flow arrow on aftermarket filter ) I discovered the error bypassing the filter , I was to say the least, delighted! However after correcting that, I was still getting the ominous FI light, which I havent seen since last December, I narrowed it down to temp related ( above 30 deg celcius) i await hot temps again as i have covered approx 6000 km since last heat wave with no issues at all. Anyway, my message for what it is worth, check and double check ALL the basics before laying out too much money.
I'm thinking it's a heat/ECM issue as well.
04 w/48K miles - I bought this bike in May and did a few things to erase the time it sat - fluids, spark plugs, 5 way T and vacuum lines. THEN the F1 (26 I believe) came up. After much reading here I called one of our local Honda shops and he said he's take a look at it for $75. I figured before I dumped a bunch of money chasing something even the gurus here can't figure out I'd give that option a shot!
When I first took it in it was 95+ temps and I could get it to code almost on command with the 4K rpm test even after both code erase techniques were used. It's in the 80's now and he's had it for about a week and can't get it to code! I went on Friday to talk to him and I couldn't get it to code.
I've got better things to do with $800, but I think the ECM/ECU is where I'm going to start!
Another contributor to that thought is that I'm only getting @35 mpg in town and sometimes top 40 on the Hwy - that seems to be about 5 to 7 mpg low!
Hopefully I'm on the right track.
I had an ECM/ECU failure on my 2003 ST1300. I tried all the other possibilities... checked the wiring for continuity, cleaned the 5-way, swapped the knock sensors to see if the error followed the sensor, but in the end the ECM/ECU was the problem. I replaced the ECM/ECU 2 years ago and have not had the FI 26 error reappear. I'm wondering if Honda knew there was a problem as they change to a different ECM/ECU in 2007 I believe.
Well I am hoping again this is the last post on the F1 light saga. After doing everything possible before replacing the ECM, We replaced the ECM and as of now and about 40 miles I am unable to make the F1 light reappear, so it looks like after all is said and done it was in fact the ECM. As far as I have read about the problem i am seeing it more in the 03, 04 05 models. I think Honda had a problem with the ECM in the beginning and I believe they knew it. If yall know a good cheep lawyer we should start a class action law suit.
I had the problem with my '07 and fixed it by replacing the ECM. IMO, there is no such thing as a good, cheap lawyer! Besides, Honda has been thru this before and they have lawyers that aren't cheap.