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Need Help DCT malfunction; Stuck in gear and refusing to shift after 40 mins of riding [Resolved 4/26/21]

Wheelee

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I worked in the Motor industry for over 40 years in Aftersales. You kinda have a dispute with Honda about the 6 hours you were charged without solving your problem and especially as you pointed out what you thought to be the problem and you have now proved it was. Worth a call.
 

lootzyan

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Did the old, problematic shift motor have the smell of burnt electrics?
The burning of the electric motor can occur if something prevents the rotor from turning. This would cause a sudden increase in electric current in the motor's circuit. This definitely cannot happen with this 12VDC electric motor. The motor's electrical circuit is protected by a fuse. If not, serious damage to the PCM could occur.
What happens with this shift motor is that there is a loss of contact between the brushes and the commutator, possibly when changing the direction of rotation. The motor stops turning.
 

showkey

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The burning of the electric motor can occur if something prevents the rotor from turning. This would cause a sudden increase in electric current in the motor's circuit. This definitely cannot happen with this 12VDC electric motor. The motor's electrical circuit is protected by a fuse. If not, serious damage to the PCM could occur.
What happens with this shift motor is that there is a loss of contact between the brushes and the commutator, possibly when changing the direction of rotation. The motor stops turning.
Sorry ……….but you clearly have no idea how the shift motor works.
Have you disassembled any failed shift motors ?
There is no fuse protection on the shift motor.
Its PCM controlled. With forward and backward rotation.
They are a permanent magnet stator witha brushed armature.
They can go intermittent and they can have a very distinct burnt smell.
 

lootzyan

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Sorry ……….but you clearly have no idea how the shift motor works.
Have you disassembled any failed shift motors ?
There is no fuse protection on the shift motor.
Its PCM controlled. With forward and backward rotation.
They are a permanent magnet stator witha brushed armature.
They can go intermittent and they can have a very distinct burnt smell.
What is this childish game? Who needs it?
You accusing me of a lack of knowledge about electrical circuits and devices, DC motors. For this you must have at least the knowledge of the basics.
Do you want to play the game of kindergarten kids - I will show you mine when you show me yours ...?
How does DCT shift motor work? I have already described it a few times on this forum. I will not repeat this as a response to your provocation.
In fact, I have a used shift motor in my garage that was replaced by one of the members of this forum. Of course I took it apart (very easy). There is no smell of burnt insulation. After thorough cleaning, it may be useful in the future as a temporary replacement. Do you have something like that?
You say this shift motor has no fuse.
Do you understand what an electrical circuit is and how to read a wiring diagram?
NC DCT has a fuse to protect the PCM and shift motor circuit. Of course, this is the basis of circuit design.
But you don't really need this knowledge.
 
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TheIronWarrior

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You say this shift motor has no fuse.
Do you understand what an electrical circuit is and how to read a wiring diagram?
NC DCT has a fuse to protect the PCM and shift motor circuit. Of course, this is the basis of circuit design.
I have the circuit diagrams for the 2012 models, not sure if the 2016 models have significantly different wiring or not so this may not be strictly applicable.
There is NO fuse dedicated to the shift motor. The shift motor connects directly to the PCM and nothing else. It's hard to tell (because there's no details of the internals of the PCM itself), but based on the diagrams I would assume the shift motor circuit is tied to the PVB fuse, which is 30 amps, leading IN to the PCM. (Does anyone know what PVB stands for?) Note, the PCM has 4 other fuses IN shown in the DCT system diagram, but troubleshooting for the shift motor seems to indicate the 30A PVB fuse is tied to the function of the motor. To be abundantly clear, the PCM HAS a fuse (or 5) for circuit protection, the shift motor DOES NOT HAVE an additional fuse for circuit protection.
Unsure what circuit protection exists WITHIN the PCM itself, but I find it highly unlikely it would be impossible to burn out the 12VDC shift motor. Assuming the PCM doesn't afford any additional circuit protection, the motor could potentially be subject to 360W (12V, 30A) before blowing the fuse.

Assuming the circuit protection is not adequate to keep the motor from burning out (and I'm not seeing any convincing evidence in the available technical data that there is) there are many reasons a motor could burn out.
Mechanically, as you mentioned something preventing the shaft from rotating would cause a current spike. Alignment of the motor and gear train or bearing failures could cause excess torque on the motor. Recall that while the reduction gear train is sealed, the motor itself is outside the engine, only "sheltered" by the lower belly fairing. Lots of opportunity for the motor to get knocked about.
Vibrations or other wear can cause some of the insulation on the windings to break down. Shorts inside the windings can bump the current enough to cook the wiring.

Considering the OP's post a few lines back that the old motor got very hot (enough to instantly evaporate water sprayed on it) and the new one does not, it sounds like the old one had an internal short.
Your statement that it was likely a loss of connection at the brushes (open circuit) seems unlikely considering the old motor was allegedly heating up excessively. Generally, shorts heat up, opens don't.

You mention you have a failed disassembled motor in your possession? Can you post some photos of the disassembled motor? I'd be interested to see what everything looks like inside the case.
 
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showkey

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What is this childish game? Who needs it?
You accusing me of a lack of knowledge about electrical circuits and devices, DC motors. For this you must have at least the knowledge of the basics.
other than everything in post #64 is wrong………..

quote:
“The burning of the electric motor can occur if something prevents the rotor from turning. This would cause a sudden increase in electric current in the motor's circuit. This definitely cannot happen with this 12VDC electric motor. The motor's electrical circuit is protected by a fuse. If not, serious damage to the PCM could occur.
What happens with this shift motor is that there is a loss of contact between the brushes and the commutator, possibly when changing the direction of rotation. The motor stops turning.”

In your …..who needs this post ………….you changed your fuse theory.

Reality is……..So far in the few shift motor failures…….there have been no PCM damage reports.

The shift motor is used on all DCT models like GL, Africa Twin, NC and many ATV with Electronic shift are the same design, many are the same manufacturer. Many are the exact same part used over many models.

At this point the hot motor winding and burnt smell is one mode of failure that appears in the small number of total failures to be quite common.
 

lootzyan

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...There is NO fuse dedicated to the shift motor. ...
Did you expect to find a fuse labeled only to protect the shift motor? Why? Can there be more electrical devices on one circuit?
But I can see that you are on the right track. Keep digging in the Service Manual. There is enough information there.
I can only repeat what I wrote previously. What happens with this shift motor is that there is a loss of contact between the brushes and the commutator, possibly when changing the direction of rotation. Nothing is blocking the rotation of this shift motor. There is no shift motor overheating. Most of the time this motor is idle. (Just like your left foot when changing gears in a manual transmission). There are only a few rotations of the rotor to change gears.
The only repair of this shift motor is to replace the brushes or thoroughly clean of the commutator.
 

TheIronWarrior

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Did you expect to find a fuse labeled only to protect the shift motor? Why? Can there be more electrical devices on one circuit?
But I can see that you are on the right track. Keep digging in the Service Manual. There is enough information there.
I can only repeat what I wrote previously. What happens with this shift motor is that there is a loss of contact between the brushes and the commutator, possibly when changing the direction of rotation. Nothing is blocking the rotation of this shift motor. There is no shift motor overheating. Most of the time this motor is idle. (Just like your left foot when changing gears in a manual transmission). There are only a few rotations of the rotor to change gears.
The only repair of this shift motor is to replace the brushes or thoroughly clean of the commutator.
It sounds like you think you have all the answers but for some reason refuse to actually give them.
If you know that "there is enough information" in the service manual that I have to "keep digging" for, why don't you just quote the manual, or give me a page and paragraph reference to look up?

The OP literally listed "hot motor" as a symptom of his failure.
One of two things is possible:
1) He's lying about having a hot motor, or
2) You don't know as much as you think you know.

You are describing a single mode of failure and making the claim that it is impossible for the motor to fail in any other way. Anyone with any sort of respectable technical background knows that this claim lies somewhere between (and inclusive of) "extremely extremely unlikely" and "impossible". Windings can and do break down. Mechanical damage to the motor housing and mount can cause misalignment and binding. Sure, brushes can lose contact, but as you say, will not lead to a hot motor. Where the OP has listed hot motor as a symptom and several others have indicated burnt motors, an open circuit specifically due to worn brushes can be concluded to NOT be the ONLY failure mode of this motor. Unless a bunch of strangers on the internet are ganging up on you for some reason, your claim cannot be true.
 

670cc

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It sounds like you think you have all the answers but for some reason refuse to actually give them.
If you know that "there is enough information" in the service manual that I have to "keep digging" for, why don't you just quote the manual, or give me a page and paragraph reference to look up?

The OP literally listed "hot motor" as a symptom of his failure.
One of two things is possible:
1) He's lying about having a hot motor, or
2) You don't know as much as you think you know.

You are describing a single mode of failure and making the claim that it is impossible for the motor to fail in any other way. Anyone with any sort of respectable technical background knows that this claim lies somewhere between (and inclusive of) "extremely extremely unlikely" and "impossible". Windings can and do break down. Mechanical damage to the motor housing and mount can cause misalignment and binding. Sure, brushes can lose contact, but as you say, will not lead to a hot motor. Where the OP has listed hot motor as a symptom and several others have indicated burnt motors, an open circuit specifically due to worn brushes can be concluded to NOT be the ONLY failure mode of this motor. Unless a bunch of strangers on the internet are ganging up on you for some reason, your claim cannot be true.
Doesn’t the motor normally get hot because it’s attached to the engine? It doesn’t sound like the elevated motor temperature was due to motor failure, rather it was due to the engine being hot.

16DCT said, “Update: It happened again while on a ride last night about 40 minutes into the ride. I've noticed that it happens when the engine is warm

While I was waiting for the bike to cool down, I removed the front sprocket cover to access the Ratio Control Motor and it was extremely hot to the touch, scathing hot!”

I would think any part of the engine would hot after 40 minutes of riding, including the shift motor. I’d guess the shift motor failed when it got hot; it didn’t get hot because it failed.
 
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lootzyan

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...If you know that "there is enough information" in the service manual that I have to "keep digging" for, why don't you just quote the manual, or give me a page and paragraph reference to look up?
I said "keep digging" to find information which fuse protects PCM and shift motor circuit. And you're right that this is PVB fuse.
I did not say anything that you will find there detailed information what causes the defective work of shift motor. Honda hasn't gone that far. My logical guess is that this is the loss of contact between the brushes and the commutator. I have proof of this at least in one case. There are a few more reports on the web from DCT owners.
 

TheIronWarrior

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Doesn’t the motor normally get hot because it’s attached to the engine? It doesn’t sound like the elevated motor temperature was due to motor failure, rather it was due to the engine being hot.

16DCT said, “Update: It happened again while on a ride last night about 40 minutes into the ride. I've noticed that it happens when the engine is warm

While I was waiting for the bike to cool down, I removed the front sprocket cover to access the Ratio Control Motor and it was extremely hot to the touch, scathing hot!”
Possible, but he also says that the new replacement motor does not seem to get as hot. Check Post #56.
"After my 84 mile ride last night I took a spray bottle and sprayed water on the shift motor and it was not hot enough to instantly evaporate the water. This is in contrast to my old shift motor which I sprayed water on upon taking it home from the dealer (roughly 30 miles) and it instantly evaporated the water."

It's possible that other factors impacted the temperature difference, but combining an observed temperature difference with the fact the new motor solved the issue, I'd suggest the hot motor was likely a symptom rather than a coincidence.
 

TheIronWarrior

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I said "keep digging" to find information which fuse protects PCM and shift motor circuit. And you're right that this is PVB fuse.
I did not say anything that you will find there detailed information what causes the defective work of shift motor. Honda hasn't gone that far. My logical guess is that this is the loss of contact between the brushes and the commutator. I have proof of this at least in one case. There are a few more reports on the web from DCT owners.
There are 5 fuses in the PCM circuit:

ILLUMI/STOP/HORN - 7.5A
ENGINE STOP - 7.5A
FI - 15A
SUB PVB - 7.5A
PVB - 30A

These are all downstream from the 30A Main fuse (which makes perfect sense). Again, from my first post, looking through the service manual suggests the shift motor is on the 30A circuit. I didn't need to "keep digging" for this, I had already stated it in my previous post.

You're now downgrading your assertion the only failure is worn brushes to a "logical guess" now? Because a few posts ago it was "what happens" and "the" way these fail, and that burning these motors "definitely cannot happen".
Seeing it once first hand and noticing a few records online is what you've offered to support your worn brushes theory. Interestingly enough, that's the same amount of evidence I see for the burnt out motor, which as we recall according to you "definitely cannot happen".

In general you seem quick to disagree with any opinion that isn't your own, but unable to provide any convincing argument why your assertions should be given more merit than the one you refute.

I am in no way saying worn brushes couldn't be the OP's issue and that the hot motor was be purely coincidental, but faced with the descriptions I've seen and the evidence presented, I would think a burnt motor is more likely, and certainly not impossible.
 

670cc

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Possible, but he also says that the new replacement motor does not seem to get as hot. Check Post #56.
"After my 84 mile ride last night I took a spray bottle and sprayed water on the shift motor and it was not hot enough to instantly evaporate the water. This is in contrast to my old shift motor which I sprayed water on upon taking it home from the dealer (roughly 30 miles) and it instantly evaporated the water."

It's possible that other factors impacted the temperature difference, but combining an observed temperature difference with the fact the new motor solved the issue, I'd suggest the hot motor was likely a symptom rather than a coincidence.
For meaningful “observed” temperature comparisons, infrared temperature readings of engine vs shift motor would help greatly.
 

lootzyan

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After reading OP's threads again (last update from April 26, 2021) I am more convinced that the problem with his shift motor was bad brush contact with the commutator.
The OP admitted that shift motor was extensively tested in the dealer's shop. "Cold" tests showed no damage to the shift motor. But the problem with changing gears occurred while riding.
Dust from brushes and increased temperature could reduce the brush spring tension, which resulted in higher current resistance across the brush-commutator connection, resulting in excess heat, sparking and the occasional loss of contact. After all, the OP bike has more than 48,000 miles. It was more than enough for this shift motor.
 

TheIronWarrior

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For meaningful “observed” temperature comparisons, infrared temperature readings of engine vs shift motor would help greatly
Absolutely, but with the lack of hard data, the subjective observations are all we have to go on. Any conclusions drawn have to accept a significant degree of uncertainty.
What stands out to me is under what appears to be similar conditions (not enough data to conclude) there was a noted difference in shift motor temperature. Impossible to say if this was expected or not, but it points my thought process toward the excessive heat being either a cause or a symptom rather that completely unrelated, but it's impossible to say for certain.


After reading OP's threads again (last update from April 26, 2021) I am more convinced that the problem with his shift motor was bad brush contact with the commutator.
The OP admitted that shift motor was extensively tested in the dealer's shop. "Cold" tests showed no damage to the shift motor. But the problem with changing gears occurred while riding.
Dust from brushes and increased temperature could reduce the brush spring tension, which resulted in higher current resistance across the brush-commutator connection, resulting in excess heat, sparking and the occasional loss of contact. After all, the OP bike has more than 48,000 miles. It was more than enough for this shift motor.
You can have shorts and opens that only appear under heat within the windings themselves as well, which would also fit the described symptoms. I feel like winding failures are more likely than brush failures due to high heat, but I'm not going to say it couldn't be the brushes. Note the high heat was first off a subjective observation and may not be actually related to the failure, and secondly, if we accept that the high heat is related to the failure, we still cannot determine whether it is a cause or an effect. There is not enough information to make a solid conclusion without more troubleshooting. It even could be that when the motor case heated up to a certain degree (from conduction from the engine case) the motor shaft would bind either due to expansion or misalignment, though that seems less likely (but still possible).

I had a cam position sensor on my VW go out, but it would only drop signal above a certain temperature. Chasing that intermittent fault was a nightmare because the sensor would work fine for cold starts, and as long as it had a signal at the beginning, when the signal dropped out the engine would run fine based off the crank sensor alone. Hot starts were impossible and I would basically be left stranded until the engine cooled down enough. What actually showed up with the MIL was a code for the valve advance, and the first recommended "fix" was to change the oil control valve for the advance gear. Not being one to throw parts at a problem until I can actually diagnose it, I got my hands on an oscilloscope and probed any sensors and actuators that I thought might be related to the fault (actual fault, not MIL code) until I watched the cam position signal drop out at a certain temperature. It was consistent in terms of temperature, once the engine got to a certain temp the signal dropped every time.

Without actually testing (may be as simple as visual inspection, but likely multiple measurements would be needed) the failed motor, it will be impossible to say conclusively what the failure was. I'd be interested to take the windings and monitor the resistance while exposing them to heat and see what happens. A failure in the windings should show up under these conditions, and no winding failures would point towards brush issues or possibly, though less likely, other electrical or mechanical problems.

I still think winding failures are the more likely cause, but I do accept that brush failure is also a reasonable theory that cannot be ruled out without further investigation.
 

MartiJ

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[Final Update *Problem solved*]: Another 91 miles on the clock which puts me at 309 miles total with the new shift motor without a single hiccup. I can now say with confidence that the issue is fixed. As expected, the Shift/Ratio Control Motor (Part: 31300-KVZ-631) was the sole problem in my particular case. The part is roughly $225 dollars on Partzilla, but I paid extra for expedited shipping. I also paid for 6 hours worth of labor costs at the dealer, and my bike was at the shop for over 2 weeks. They were unable to get the old shift motor to fail despite multiple bench tests and test riding the bike, so in theory that was a total waste of time and money. My theory for this is that they never rode it long enough to get it to the failure point (or tested the shift motor long enough on the bench).

So if you are facing similar issues as described in this thread, combined with DTC codes 24-1 and 57-1, you may have a problem with the shift motor. It's very easy to replace at home. You will need to remove the left side belly pan, the front sprocket cover, the exhaust guard, and after that it's just 3 bolts to remove the old motor and install the new one.
Thanks for sharing your story. For those that are wondering about how to get at the shift motor and what's inside this video is helpful:

 

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To the OP , did you clean the shift motor as outlined on the u tube video and keep it as a spare.
I read on a post where someone had similar issues on a road trip and pulled his shift motor and cleaned it and it's been working fine for thousands of miles since. I have a noise / growling coming from my rt side clutch cover , no shifting issues , but I'll be pulling it apart to check the shift pin and might pull apart the shift motor to clean it as preventative measure @ that time
 

loudpipessaveslives

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I tooked my nc 700 dct to a honda SC its now been 3 months i have received 3 different quotes( shifting pin and a drum of some kind new oil,second quote was a new rear sprocket, now they want to see if a new PCM would fix the problem.) Im in South Africa. So be careful not to accept quotes too quickly you are a customer and you deserve to be informed why they want the new part.
 
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