[csdexter]

Since people appear afraid to ask the question, I will:

• the CTX1300 has the red DLC connector. Is it the same protocol as on the GL1800? Will it work with the Blue Monkey OBD-H01?
• has anyone caught any wind of the protocol details? Having a single tool sold by a single company is like not having any tool at all -- no competition is BAD.
• rumor has it it's ISO K-line on pin 3 of the connector but the higher level protocol is either not OBD II or it needs a special "knocking" sequence to switch to OBD II, any extra info on that?

But why?

• because it's my bike, I paid for it in full and therefore I want to enjoy it in full. This includes knowing what goes through the ECU's mind at every instant.

 

[csdexter]

Hidden gems

I spent some time with the wiring diagram and discovered a few interesting things:

• the audio unit has headphone output and aux input, but they are not wired at the harness-side connector. Opportunity! Also, it has inputs for switching via discrete buttons, but they ale also not wired and the unit is driven via CAN
• the dashboard display is driven via CAN by the ECM, as well as by discrete inputs for each idiot light. There are wires left there for the ETC light (both green and orange) as well as for the foglight indicator
• the DLC connector has indeed a K-line wire to the ECM and the two pins you have to short to read trouble codes are actually a bus line that (when shorted) connects the ABS modulator to the ECM

I see a logic analyzer in this bike's future ;-)

 

[csdexter]

More stuff:

• I was slightly wrong about the Dashboard and Audio Unit connections: the Audio Unit talks to the Dashboard via CAN, while the ECM has a dedicated transmit-only line. The Audio Unit is directly connected to its switches and guessing by the low number of wires involved, they're resistance-coded
• the manual is rather unclear over what blinks for who's error codes. Careful examination of the schematic shows both the ECM and the ABS have SCS lines which are tied together and shorted to ground at the DLC connector during diagnostic. The ABS warning indicator blinks for ABS's codes; the MIL blinks for ECM's codes
• there are two option connectors, labeled "front" and "rear". The front one, as discovered by another forum member, is meant for the fog lights: it has ACC, FOG, HI and GND. ACC is switched battery power, HI is the high beam line (connected to battery power when the high beam is on) and FOG is the control line for the fog light indicator in the dash (short to GND to turn on). The rear one has B+, ACC, BLS and GND. B+ is unswitched power and BLS is the brake light line (connected to battery power when brakes are applied and the brake light lights up). My guess is this is for a future trunk spoiler with a stop lamp, like on the GoldWing
• the dashboard has three unused circuits of particular interest: ILLUMINATION, TPMS and LOW_TIRE_P. Apparently, owing to current regulations, the lights come on automatically so the separate illumination power line was left open. Also apparently, this dashboard is supposed to support bikes with a tyre pressure monitoring system. Since there don't seem to be any LED indicators for that, I'm guess pulling those lines low shows icons in the graphic area of the dash -- can't wait to test

More as I get time to get into its guts ;-)

 

[bob]

@Dexter- have you actually found that rear option plug? It may be an International item that is missing on U.S. bikes. The service manual shows where it is mounted on the right side under the seat but my bike only has an empty mount there and not connector or cable for that. :350x700px-LL-66dd6d

I am currently using the front option plug ACC and ground connections for my GPS and soon will modify to add in my Gerbing heated gloves on the same wires. I have the factory spec pins to insert in the dummy plug for it. I've posted on this in another thread here.

 

[csdexter]

Same on my bike: empty mount on the right but there is a suspect connector tape-bound to the 12V cigarette socket cable right in front of the mount. Will have to investigate.

The CTX1300 is really funny with regards to the US/EU thing, it's probably the first bike I see that the OEM tried to get away with having a single model in both markets The always-on indicators on the front, the configurable km/mi odometer, the reflectors on the saddlebags and so on -- they appear to have tried really hard to fight the lawman, hats off to them.
It's the same thing with the service manual: everybody else usually has two different manuals whereas Honda even goes as far as to list tools that are supposedly available in EU vs. the US. This also shows that Honda "failed to be IBM" and allowed (or even asked?) its local arms to do their own research with regards to servicing, hence the differing tool sets.

About the schematic, I plan to re-draw it as vector so that it's less 1980s and more 2014 and then derive two more schematics for it: a purely electric one so that you can actually follow the function of the circuits without tracing the maze and a harness one so that you can look at the paper and know where stuff is physically on the bike.

Sadly, they don't do diagrams like they used to so I have to do the legwork.

Finally, the joint connectors are awesome: they're used at the factory to test each individual circuit and device without having to cut wires or insert probes: you just take the joining half of the connector out, plug a power sequencer in and fire away. Very Honda, I like it

 

[Kookopelli]

Man, that is a bunch of Greek to me, but it sounds like you guys will soon be devising cool things and sharing them with us non-techie types, including lots of pictures and step-by-step directions. I hope csdexter will share his diagrams when he has them done...please?

 

[csdexter]

Kookopelli> my religion is knowledge, I'm the kind that would always rather teach you how to fish than give you a cooked fish ;-) Of course everything I discover, draw or write will be shared here for the benefit of all.

 

[csdexter]

Some of the eBay stuff has arrived so I've crafted a Sumitomo-HM to OBD-II cable. I'm still waiting for the HM female housing to arrive, but if I get inpatient I can just stick the pins in the bike connector. I have an ELM327 box which I don't really expect to work from the first attempt (i.e. with one of the well known applications, such as Torque), but rather use as a starting point.

Few people know the ELM327 is not just a dumb OBD-to-RS232C pipe, but rather a quite capable chip that can be talked to and asked to do interesting stuff. I plan to try and get it to talk to the ECU like that at first and we'll see what happens.

 

[sleepngbear]

Some of the eBay stuff has arrived so I've crafted a Sumitomo-HM to OBD-II cable. I'm still waiting for the HM female housing to arrive, but if I get inpatient I can just stick the pins in the bike connector. I have an ELM327 box which I don't really expect to work from the first attempt (i.e. with one of the well known applications, such as Torque), but rather use as a starting point.

Few people know the ELM327 is not just a dumb OBD-to-RS232C pipe, but rather a quite capable chip that can be talked to and asked to do interesting stuff. I plan to try and get it to talk to the ECU like that at first and we'll see what happens.

Now yer talkin some seriously interesting poop. I'm very curious to see what you're able to dig up.

 

[csdexter]

Mandatory photo (hi-res):

My wires have the same colour as the ones on the bike (credits: Kojaycat.co.uk), the brown one is the SCS wire. I'm still waiting for a small switch I ordered to show up so that I can wire that in as well (you would connect SCS and GND when you want the ECU and ABS to wink at you any stored error codes).

 

[csdexter]

I finished the cable yesterday (small SPDT toggle switch and Sumitomo HM connectors arrived last week) and installed it on the bike.

As expected, the ELM327 when driven by Torque on Android fails to handshake with the bike. The next step is to grab a copy of the ELM327 command reference and my laptop and spend some 1/2h (before she heats up too much) trying different things in an attempt to get K-Line communications to run.

Failing that, I'll get a copy of the ISO K-line specs and my trusty logic analyzer and go one level deeper. Next candidates for eavesdropping are the M-TXD line between the ECU and the Dashboard and the comm lines between the HISS RFID module and the ECU.

Something's gotta give!

Oh and, Honda, if you're reading this: a heartfelt "Up yours!". We're not in the '80s anymore, grow the **** up and stop telling Keihin to make the ECUs pretend they're nuclear rocket control boxes. It's not like I don't have a JTAG adapter or don't know how to dissolve potting EPOXY, you know? It's also not like I couldn't reimplement your "precious" black box with a couple ATmega328s so stop acting like a frustrated teenager and make the **** thing OBD-II compliant!

 

[csdexter]

Picture of the finished cable, research is still pending (hi-res):

 

[csdexter]

Santa got me a diagnostics interface that is known to work with the CTX1300. For obvious reasons, I cannot mention the make/model, but I will be mentioning all results of my research here.

 

[bugmenot]

Any updates?

 

[csdexter]

The interface works with the bike as advertised. I'm not 100% satisfied with the number and choice of parameters available and neither am I 100% satisfied with the vendor's explanation that "what you see is exactly what the ECU is providing, no more, no less".

I haven't gotten to attaching a logic analyser to the interface to see why this one works and a standard ELM327 for cars doesn't.

There appears to be some advanced work online on accessing the internals of Keihin ECUs, but it's targeted at the model used on sport bikes (of course). Also, said work involves drilling the case open and attaching to the JTAG port which is not "fair game" according to my principles.

More updates as soon as I get to doing a traffic capture with the logic analyser (note I'm not retired so I still have to work to pay the bills).

 

[GonzoB]

Hi.

I've got a CTX700 on which I've done some work you may be interested in:

Here

The Elm327-based units fail for a number of reasons:

• the init sequence is standard OBDII and the honda one isn't
• the inability to send a 4-char message, which the Honda needs to start
• the checksum is calculated differently than the Honda one.

I was Googling for other people who had done work similar to mine, and I came across this thread, so I thought I'd share.



Gonzo

 

[csdexter]

That, Sir, is just pure awesomeness.

/me takes a bow

Thanks for sharing, power to the geeks!

 

[Davetac1]

Some wheres on the CTX,there is an ALDL [assembly line diagnostic link] connector plug,just like the one used in your car or truck on the left underside of the dash.In order to sell any motor vehicle here in the States built after a certain date,the vehicle in question MUST be equipped with the OBDII system and that ALDL connector plug for diagnostic purposes.So it's gotta be there.My Tbird has one!!And then, for around 40 bucks,you can buy a small pocket size diagnostic plug-in tool with the male plug on it to plug right into the ALDL connector plug on the vehicle.I bought one and carry with me in the bike for road side diagnostics ,whether it be for my scooter,or someone else' that I may run into on the road with a problem.[check engine light on] Dave!!!

 

[csdexter]

Said this so many times, here goes once again:

• the regulation you're quoting applies to cars (4 or more -wheeled vehicles) in both US, Japan and the EU. Note: motorcycles not included
• having a means for authorized service personnel to "dial-into" the ECU is one thing, having *the* connector in the standard wired *exactly* like in the standard and running *the* protocol in the standard is another thing. Once again, the mandatory aspect of that standard applies to cars only
• most unfortunately, even the standard which does apply to cars is not 100% a standard, allowing far too much leeway in how it's implemented and this is the reason things like the ELM327 will work for 99% of cars and 99% of the really basic stuff (speed, mixture, injector pulse, trouble codes etc.) -- but if you really want to read *all* the stuff your car knows (or, heaven forbid, modify it), you will need to either reverse engineer the non-standard part of pay a lot of money for a brand-specific interface.

Nothing written above means a motorcycle (actually, ECU; so Bosch, Keihin etc.) manufacturer cannot decide to provide the exact same interface as on a car (i.e. same connector, same protocol), but until the very day laws mandate it, they ain't gonna do it.


Coming back to our dear CTX1300:

• the connector is *not* standard (4-pin Sumitomo HM .090" instead of 16-pin SAE J1962)
• the transport protocol *is* one of the ones from the standard (K-Line as in ISO 9141-2 or ISO 14230-4)
• all of the higher protocol levels are *not* standard, as explained in brief by GonzoB above

Given the newly available information (thanks GonzoB!), I will try to come up with a miniaturized version of GonzoB's solution that can either plug into a variety of displays (I'm a big fan of E-Paper and VFDs, other people have other preferences) OR be used as an ELM327 work-alike so that you could use, e.g. Torque on your phone with the CTX1300, even if the underlying protocol is different.

 

[GonzoB]

Hi CSD.

A few notes:

• I got a lot of help from forum.pgmfi.org . I've posted my findings there so it's all in one place, incl some sniffed results from my commercial diag tool. Here's the link, I think (The site is down at the time I posted this).
• As you saw on the CTX700 forum, I found that a smartphone makes a good touch-screen display. You use it as a hot-spot for the on-board computer to tether to via wifi, then do all the programming in html/php. All you need to supply to the phone is power.
• The main reason for doing the work in the first place (other than it being fun) is that the 700 has a 12.4-litre tank and a crappy fuel level gauge, so planning fill-ups becomes really important. Hence my inclusion of the fuel level data and the distance-to-empty.
• Others have successfully used arduinos with soft-serials to get the 10400baud and the initial handshaking. I used a FT232RL because I had the RPi

Gonzo