Need Help Fault code - Engine light flashing

[Julien]

Hi everyone, this is my first post here, and I am really excited to be part of this community.
I bought a second-hand NC 700 SA 2012 model a few years back. I love my bike and want to give it the care it needs.
The engine light recently started blinking (even when the bike is not running). The fault is 8 slow blinks followed by 6 quick blinks followed by 5 slow blinks followed by 4 fast blinks. It goes on over and over. (See the video for a more visual description

)
I noticed that if I let the bike idle after a bit, the light stays solid, and the fan does not kick in. (I feel like it's saying it's overheating). I looked on Google but couldn't find anything with the same code.

Does anyone know what it would be or where to look to match the blinking lights with a fault?
Thank you for reading.

 

[lootzyan]

Most likely bad contact at the connectors.

 

[670cc]

The 86 code, combination meter communication, is often linked to low voltage due to a bad battery or poor cable connections at the battery. What is the status of the bike’s battery, or it’s age? You may benefit from inspecting/cleaning/tightening the battery connections, and checking battery voltage with a voltmeter.

 

[Klap]

As @670cc has mentioned, battery issues , poor connections, corroded connections, etc can cause that fault.

Does the bike live outdoors? It is, after all, 11 years old, and might just need some love. A little cleaning , and some dielectric grease might cure it.

 

[lootzyan]

The 86 code, combination meter communication, is often linked to low voltage due to a bad battery or poor cable connections at the battery. ...

For many years a statement like this has been made on this forum and I have never been able to find a true technical description that this is actually happening.
Except "He said" as proof.
It makes no technical sense if one understands closed electrical circuits. And I'm sure you understand that. As you recently said about yourself that you are "an electrical person... For 40 years" and that "Troubleshooting a battery circuit is child's play".
First of all, what does the term "a bad battery" mean to someone? For me, it only has one meaning. The amount of energy accumulated in the battery is insufficient to start the vehicle's engine.
Then what does "poor cable connections at the battery" mean? Is it possible to start the engine without problems if there is a relatively large voltage drop on the connections due to "poor cable connections at the battery"? It's like running with loose laces on your shoes. It is hard to imagine that someone with many years of experience riding a motorcycle will not notice the difficult start of the engine.

 

[670cc]

For many years a statement like this has been made on this forum and I have never been able to find a true technical description that this is actually happening.
Except "He said" as proof.
It makes no technical sense if one understands closed electrical circuits. And I'm sure you understand that. As you recently said about yourself that you are "an electrical person... For 40 years" and that "Troubleshooting a battery circuit is child's play".
First of all, what does the term "a bad battery" mean to someone? For me, it only has one meaning. The amount of energy accumulated in the battery is insufficient to start the vehicle's engine.
Then what does "poor cable connections at the battery" mean? Is it possible to start the engine without problems if there is a relatively large voltage drop on the connections due to "poor cable connections at the battery"? It's like running with loose laces on your shoes. It is hard to imagine that someone with many years of experience riding a motorcycle will not notice the difficult start of the engine.

If you want answers to your questions, they might be found in the posts made by people that have addressed the 86 fault by focusing on the bike’s battery and it’s electrical connections. A forum search of the fault code turned up many past posts. I have not experienced the 86 code nor had any reason or opportunity to troubleshoot it. Given that people have reportedly had the fault and solved it, reading about their experiences would have some value. That is why I wrote the simple but true statement, “The 86 code . . . is often linked to low voltage due to a bad battery or poor cable connections at the battery.” I made no statement as to the logical or technical reason for that link or association; I only suggested that the association exists.

I also carefully chose the word “may”, as in that the OP “may” benefit from checking the battery/connections.

 

[lootzyan]

If you want answers to your questions, they might be found in the posts made by people that have addressed the 86 fault by focusing on the bike’s battery and it’s electrical connections. A forum search of the fault code turned up many past posts. I have not experienced the 86 code nor had any reason or opportunity to troubleshoot it. Given that people have reportedly had the fault and solved it, reading about their experiences would have some value. That is why I wrote the simple but true statement, “The 86 code . . . is often linked to low voltage due to a bad battery or poor cable connections at the battery.” I made no statement as to the logical or technical reason for that link or association; I only suggested that the association exists....

I didn't ask the question so I'm not looking for an answer.
And looking on the forum for "code 86" related to a bad battery connection or a faulty battery is exactly what I said before: "He said" as evidence.
The Honda Service Manual does not contain such a link and rightly so because it does not make technical sense. The Service Manual mentions a possible faulty digital connection of the communication cable, and that makes sense.

 

[670cc]

I didn't ask the question so I'm not looking for an answer.
And looking on the forum for "code 86" related to a bad battery connection or a faulty battery is exactly what I said before: "He said" as evidence.
The Honda Service Manual does not contain such a link and rightly so because it does not make technical sense. The Service Manual mentions a possible faulty digital connection of the communication cable, and that makes sense.

Sorry; it’s just that there were three sentences in your post #5 that ended with question marks, so I interpreted them as questions.

I didn’t ever dispute anything you said in post #2. In fact, I clicked the Like button. I then pointed to an idea based on other forum members’ past experiences; while you had pointed to the manual. The OP should have some options now.

 

[670cc]

Let me offer to the OP a possible hypothesis for why the battery or the battery connections may apply to these symptoms. One fault code, 54, lists low voltage in the circuit in it‘s description. The other code, 86, is mentioned more often by the forum than any other code, from my recollection. It seems either the combination meter has a poorly designed connector, or there may be another cause. If the battery is old, weak, or otherwise has high internal resistance, or if the battery cable connections are resistive, there may exist a fine line where, during cranking, the voltage drops just enough to trigger the faults. Perhaps the combination meter communication circuit is extra sensitive to low voltage, as well as possibly the bank angle sensor. Hypothetical scenario: Key is turned on, fuel pump pressurizes, start button pushed and starter cranks enough to spin crank, EFI still has enough voltage to control injectors, YET, during cranking the system voltage drops below the tolerance for the bank angle sensor circuit and/or the combination meter communications, so right there the code(s) is/are set. Engine started and runs normally, alternator brings voltage up, motorcycle runs fine but the fault code history remains. I’m not saying that is what is happening, but it is a hypothesis yet to be proven.

I do not have access to a motorcycle that is actively showing these codes, so I cannot do any troubleshooting on my own to confirm the hypothesis. Nonetheless, addressing the battery and/or it’s connections has been reported as an apparent solution by member(s), so without data or proof to the contrary, I’m not going to dismiss the possibility. It’s worth a looky. The battery health and connections could be checked rather quickly, then move on to other possibilities.

Julien, there is a way to reset/erase the MIL code blinks, should you get to the point of needing to do so. Also, to address your comment about the fan, it should rarely run. The bike might need to set still idling for 10 minutes or more, depending on ambient temperature, before the fan would come on. There is also a high temperature warning light on the dash that would light in an extreme overheat scenario.

A semi-related event happened to me on a small car with a very low capacity battery. I was able to start the car engine, but the transmission controller displayed a fault message and went into a limp mode. So I could drive the car but the transmission (a DCT) shift patterns were significantly altered. I disconnected the battery to remove all power and installed a proper one and the fault cleared, and the car behavior returned to normal. My observations strongly suggested to me that low voltage during starting triggered the transmission fault, even though the engine did successfully start. Even though the transmission called a fault, there was actually nothing wrong with the transmission.

 

[mzflorida]

I'm actually surprised on how quickly the ignore function works here on this website. Just like that, done.

 

[lootzyan]

...why the battery or the battery connections may apply to these symptoms. One fault code, 54, lists low voltage in the circuit in it‘s description...

I don't know why you interpret the Service Manual this way. It has nothing to do with possibly low battery voltage.
From the description of the DTC 54-1 test, it appears that this is a test to check if there is a short circuit in the Bank Angle Sensor circuit. This is due to the fact that the ECM receives a signal that there is a voltage close to 0V in the sensor circuit (Bank Angle Sensor LOW VOLTAGE).

 

[Julien]

The 86 code, combination meter communication, is often linked to low voltage due to a bad battery or poor cable connections at the battery. What is the status of the bike’s battery, or it’s age? You may benefit from inspecting/cleaning/tightening the battery connections, and checking battery voltage with a voltmeter.

The battery was weak, so I just got a brand new one to eliminate that potential fault. And mine was also due for a change

 

[Julien]

Let me offer to the OP a possible hypothesis for why the battery or the battery connections may apply to these symptoms. One fault code, 54, lists low voltage in the circuit in it‘s description. The other code, 86, is mentioned more often by the forum than any other code, from my recollection. It seems either the combination meter has a poorly designed connector, or there may be another cause. If the battery is old, weak, or otherwise has high internal resistance, or if the battery cable connections are resistive, there may exist a fine line where, during cranking, the voltage drops just enough to trigger the faults. Perhaps the combination meter communication circuit is extra sensitive to low voltage, as well as possibly the bank angle sensor. Hypothetical scenario: Key is turned on, fuel pump pressurizes, start button pushed and starter cranks enough to spin crank, EFI still has enough voltage to control injectors, YET, during cranking the system voltage drops below the tolerance for the bank angle sensor circuit and/or the combination meter communications, so right there the code(s) is/are set. Engine started and runs normally, alternator brings voltage up, motorcycle runs fine but the fault code history remains. I’m not saying that is what is happening, but it is a hypothesis yet to be proven.

I do not have access to a motorcycle that is actively showing these codes, so I cannot do any troubleshooting on my own to confirm the hypothesis. Nonetheless, addressing the battery and/or it’s connections has been reported as an apparent solution by member(s), so without data or proof to the contrary, I’m not going to dismiss the possibility. It’s worth a looky. The battery health and connections could be checked rather quickly, then move on to other possibilities.

Julien, there is a way to reset/erase the MIL code blinks, should you get to the point of needing to do so. Also, to address your comment about the fan, it should rarely run. The bike might need to set still idling for 10 minutes or more, depending on ambient temperature, before the fan would come on. There is also a high temperature warning light on the dash that would light in an extreme overheat scenario.

A semi-related event happened to me on a small car with a very low capacity battery. I was able to start the car engine, but the transmission controller displayed a fault message and went into a limp mode. So I could drive the car but the transmission (a DCT) shift patterns were significantly altered. I disconnected the battery to remove all power and installed a proper one and the fault cleared, and the car behavior returned to normal. My observations strongly suggested to me that low voltage during starting triggered the transmission fault, even though the engine did successfully start. Even though the transmission called a fault, there was actually nothing wrong with the transmission.

Do you know the procedure to reset the MIL code? I would be interested in giving it a try as I just replaced my battery because the old one was really weak.

 

[lootzyan]

What do you mean by "really weak battery"? This is usually a very general term used when there is already a noticeable difficulty in starting the engine. In your video we can hear the engine running. Did you measure the battery voltage before starting the engine?
Below you have an example of the state of the battery according to Yuasa.

 

[Julien]

The battery used in the video is brand new. The one I had before when the fault started has a voltage of 3.86V after a full charge and about 4 cranks.

 

[670cc]

Do you know the procedure to reset the MIL code? I would be interested in giving it a try as I just replaced my battery because the old one was really weak.

My service manual is for 2012 NC700X. The procedure should work with your S model but the location of your service connector may differ, although the first place I would look is near the battery. Perhaps someone with an S model can help in that regard. As I understand it, you do not need to buy a “special tool”, rather you can just jumper across the terminals. Read this procedure I took a photo of, and see if it makes sense.

 

[lootzyan]

The battery... has a voltage of 3.86V after a full charge and about 4 cranks.

A battery with such a low voltage of 3.9V is not able to get the starter motor to move at all and you are talking about 4 cranks of the motor. Surely your measurement was wrong.
But that's past now.

 

[670cc]

A battery with such a low voltage of 3.9V is not able to get the starter motor to move at all and you are talking about 4 cranks of the motor. Surely your measurement was wrong.
But that's past now.

Reading post #15, the starting battery voltage before cranking was not given, only that it had a full charge. The voltage read 3.86 volts after the 4 cranks, not before.

 

[lootzyan]

Reading post #15, the starting battery voltage before cranking was not given, only that it had a full charge. The voltage read 3.86 volts after the 4 cranks, not before.

Yes you are right.
This information should be in the first sentence of post #1.
I had a similar situation today. Due to my negligence my bike had one belch when trying to start and that was it. After half an hour of charging, the next attempt to start the engine was with a slight hesitation. The engine ran for about 1 hour but there are no fault codes. The battery may need to be replaced. It will turn out after at least 10 hours of charging.

 

[tups]

Also here, I've been battling fault code 86 for about three weeks now. First it was intermittent, I thought it might be due to the pulse modifier I built into the speedo wire a few months ago. Everything looks fine under the heatshrink. Then it became persistent. Before spending half a day doing the diagnosis described in the shop manual, to probably end up in the situation 'intermittent problem/replace speedo/replace ecm', I undid the battery connections, cleaned them up nice and shiny, and gave them a spritz of contact cleaner. Reconnected, reset the clock, and... no more fault code 86 for the past 150km or so. Cleaning battery connections- it works.

Cris
2012 nc700s