Nc750x fault code p2765.. transmission fault. help needed

[wolfswater]

Hi..got a 2020 nc750x dct.. 26 k fully serviced.. few weeks ago I put optimiser on it for a few days as it not used much in winter.. next time I went out did 2 miles and engine management light came on and it stopped changing gear with only a flat line on gear selector display.. stopped bike it shifts down to first.. start again did 50 yards did again.. took home.. tryed it next day ok just 3 miles to top up fuel. Next day can't go 30 yrs before engine management light on and stuck in gear...got code reader and it says ..p2765.input/turbine speed sensor b circuit. Any help greatly appreciated..thanks

 

[Deleted member 1183]

Imho firstly look a bit closer at battery voltage

 

[wolfswater]

It appears to be all good..

 

[Aiwa]

Watching this one although (with little actual knowledge) I question the battery. Try doing a load test on the battery. Standing voltage is one thing but seeing how far it dips when a load is applied is a better indicator of battery health.

 

[lootzyan]

First, I would love to finally see some (real) technical proof that a standard OBD-II Trouble Code reader can read DTCs from NC/CTX motorcycles. Because so far, these are just non-technical suggestions from pseudo-knowledgeable participants in the forum world.
However, let's assume that this is true, so the P2765 code suggests that it is "Transmission 65 code". According to the Honda Service Manual, this means: DTC 65-1 (FRONT AND REAR WHEEL SPEED SIGNAL MALFUNCTION). Judging from your bike's behavior, that would make sense. But the motorcycle's self-diagnostic system should let you know about the DTC by shift indicator blinking "-".
But first I would advise you to go back to the state without the "optimizer" and see if there is the same behavior. You can check the front wheel speed sensor air gap. For more detailed instructions, see the Service Manual section 12.
By the way, the condition of the battery obviously has nothing to do with it, because the electrical system is powered by the alternator while riding.

 

[wolfswater]

Thankyou.. the code rear was sold specifically for NC 750 model.. but is limited . However today I had a snapon euos code reader plugged in and it brought up lots of live data including fuel trim .surprising as there are only 4 wires going to the obd plug.... unfortunately I was unable to test on road due to weather.. . Is service manual available on this forum.. thanks

 

[670cc]

Thankyou.. the code rear was sold specifically for NC 750 model.. but is limited . However today I had a snapon euos code reader plugged in and it brought up lots of live data including fuel trim .surprising as there are only 4 wires going to the obd plug.... unfortunately I was unable to test on road due to weather.. . Is service manual available on this forum.. thanks

The Honda service manual is not allowed to be on this forum as long as it is copyrighted material not made available for general distribution.

 

[lootzyan]

.. the code rear was sold specifically for NC 750 model.. .. . Is service manual available on this forum.. thanks..

Sorry, but I'm still skeptical. There are many sites that claim that their reader with adapter guarantees the correct reading of the DTC code. But from the picture you provided, it appears that the reading applies to motor vehicles. Why then does it not provide a DTC description for the NC/DCT specific code.
If you were to study the DTC Idex for the DCT in the Service Manual there are about 58 codes specific to this type of transmission only and not overlapping with the code of automatic transmissions in motor vehicles.
That's probably why Honda equips authorized service centers with its own MCS Diagnostic Tool. For us, if we don't have access to such a tool, Honda's Service Manual provides detailed instructions on how to read the DTC code. Such a Service Manual usually cost around $36 and is worth every penny.
In the US there is a note in the Owner's Manual/Consumer Information on how to obtain authorized Service Manuals.
Maybe try asking an authorized Honda dealer how to get a Service Manual.

 

[wolfswater]

Ok thanks.. is there any other way to read code on a 2020 model other than code reader.. cheers

 

[lootzyan]

As I wrote before: "Honda's Service Manual provides detailed instructions on how to read the DTC code...".
It's quite simple. But, I want to emphasize, this is only the first step, and the easiest one, anyway.
The Service Manual gives suggestions. How to interpret it depends on the level of experience.
Therefore, in your case, I suggest you revert to the original state first. PCM can be fooled if there is another device sending the wrong signal.
But maybe one of the sensors is faulty. Mine is just guesswork and without my involvement in testing it may be useless.
Here is an example from the 2011/12 models:

 

[wolfswater]

Thanks for that.. starting to get a few ideas now what I'm doing ..

 

[INTHEWIND]

As I wrote before: "Honda's Service Manual provides detailed instructions on how to read the DTC code...".
It's quite simple. But, I want to emphasize, this is only the first step, and the easiest one, anyway.
The Service Manual gives suggestions. How to interpret it depends on the level of experience.
Therefore, in your case, I suggest you revert to the original state first. PCM can be fooled if there is another device sending the wrong signal.
But maybe one of the sensors is faulty. Mine is just guesswork and without my involvement in testing it may be useless.
Here is an example from the 2011/12 models:

View attachment 51122
View attachment 51121

Special terminal shorting tool
ie: paperclip.

 

[wolfswater]

Thanks, I really appreciate the info.. ATM I've had to resign bike to back of workshop as have no time due to other commitments.. but I'm saving all these posts and hopefully can take a proper look again next month.. thanks for taking the time to help.. cheers