The ads above are Google-sponsored.
Clicking on them at every visit helps support this website!
Clicking on something INSIDE the advertisements helps even more!!

CAN-BUS (CAN) and OBDII.  What are they? Other types?
What's the future?  Speed snoop built into your bike?
What about WiFi in vehicles for diagnostics?
Cautions when using desulfation mode with Smart Chargers!

Copyright, 2017, R. Fleischer

Can-Bus is the same as Canbus, and often misspelled CANBUSS, CAN-BUSS, CanBus).  OBD means On Board Diagnostics.  OBDII or OBD2 is the second version, in very common use now. Can-Bus is, or includes, a version or type of OBD ...AND of the method of communications between items/devices in a vehicle.

Primarily, Can-Bus is a method, hardware & software; to enable communications between 'electrical & electronics things' on your vehicle; these 'things' are often partly mechanical.  Can-Bus stands for Controller Area Network, & the 'Bus' part is explained later herein.

As you will see in the section on the future, it can do a lot more than just in-vehicle communications.  While Can-Bus will be mostly discussed here, as it is installed by BMW in your bike, etc., the information is similar for any system that communicates similarly, and also for all varieties of OBDII. All modern cars have such systems; & a diagnostic plug to access it.  Can-Bus & similar systems have the ability to transmit information between components at quite high speed, & to facilitate changes in the operation of items.  OBD can do some of that, but mostly thought of as just diagnostic, retaining information in memory, until downloaded for diagnostic work. Updating vehicle software programs is also done via OBD. Manufacturer's are already experimenting with WIRELESS updating of car systems.

BMW decided to reduce the number of electrical wires & connections & hopefully reduce electrical problems, by operating just about everything, to the extent possible, using digital electronics.  There are some definite advantages, such as weight saving; manufacturing labor; & the potential for much higher reliability; fewer wires are needed for most anything.  In addition (and more importantly), the ability for the vehicle computer(s) to monitor & talk to each other about just about any function, & particularly in a very short time period, that is, at electronically high speeds, is greatly enhanced.  There are other reasons for going to something like Can-bus.   Vehicles are becoming vastly more complicated, so more & more computers or mini-computer elements are needed to monitor, produce or accept information from each other, and I will discuss these some.

In the Classic K bikes (K75, K100, K1, K1100) there is monitoring of many things going on all the time by the central computer, in order to have the ignition & fuel injection operate at near optimum, all the time.  These bikes were fairly simple, compared to later BMW models.  Some models even had computer controlled ABS braking systems. The ABS braking system (there was an early heavy system and a later less weight and more sophisticated system) controlled wheel spin &  emergency braking better than most riders could do manually.  One of the nice things about a FI motor, is that...usually....they start up quickly in any weather.  This is particularly so with 3 or 4 cylinders or more.

Later bikes than the K1, K75, K100, K1100; sort-of beginning with the K1200, had fancier systems available, and now there are very complicated computer controlled motorcycles whose systems control suspension settings, offer traction control and even stability control. Many things came about from the original basic ABS systems.

Traction control, stability control, & ABS, all require FAST information processing.  Electronics is absolutely necessary for these functions and as sensitivity and performance improved, they required ever faster electronics and more sophisticated sensors, etc .

A problem that arises from Can-Bus & other such systems, is that the electrical system is, to quite some degree, no longer relatively easy to modify with farkles, changes, & add-ons.  Adding an electrical outlet jack to a place after the ignition switch may well cause problems; usually the system detects an unusual load, or even a smart charger connection.  Typically, the easy answer is to wire accessories directly to the battery, usually via a separately added fuse or fused panel.  That often means a separate on-off switch, as the ignition switch may not be usable for that purpose.  There can be serious problems, depending on what item is added, and how wired, even if directly to the battery. In some instances, ways have been found to use a relay, energized, perhaps, by electronics that do not 'look like' loads to the Can-Bus system, even after the ignition switch.

Because of how various sensors (or connections) 'report' to the computer(s), the battery condition may become more important than previously.  Already on some vehicles we have more sophisticated monitoring for the battery, reporting to the main computer not only the state of battery voltage, but actual charge & complex charging characteristics.  Soon the systems will be able to identify a battery with higher 'impedance' (something like internal resistance), which would allow Can-Bus and other 'signals' to be disturbed by the battery condition.  Already, some systems can analyze connections for corrosion at the terminals or other faults. This is all simplified compared to what is already being incorporated into cars ...and it will all most likely be in motorcycles eventually.

Bosch invented Can-Bus in 1983 for use in Mercedes cars; & widespread use began in the late 1980's.  Can-Bus is just one of several 'protocols' of the OBD-II system.  Your car likely has "OBD"; that stands for On Board Diagnostics, & it is standard now for all cars ...the latest version has been and is still OBD-II.  A technician or you can connect a 'reader' (or other perhaps more sophisticated gadget) to an electrical plug in your car (or almost all motorcycles now since the mid-nineties).  The Technician can read out problem codes recorded by the vehicle computer well as non-problem codes. He can get a lot of information about the engine; transmission, brakes, cooling system; & much more.  A simple version was in the early K bikes and Bosch (and BMW) made those EARLY VERIONS such that you could get that information yourself without a 'reader instrument', by the number of flashes and in what order/arrangement, of such as the over-temperature lamp in the instrument pod...provided you knew the very simple method of triggering that output.; later versions are much more sophisticated.  Information now is in real live time and in computer memory

With many types of 'readers' a technician can actually make adjustments & incorporate vehicle computer updates.   Your BMW dealership has such sophisticated reading/updating/adjustment computer-analyzers.  Updating the computer functions is called 'flashing' the information is transferred to something akin to the flash memory chip in your personal computer. Many times a manufacturer will offer updates to correct some problem or other need.  These updates are obtainable by authorized repair centers.  For BMW motorcycles, there are aftermarket readers that can do many things besides reading codes and displaying those codes.  Actual changes can be made.

Various Governments have mandated these methods of computer readouts in your vehicle.  The USA Federal Government mandated that the USA comply with the International Standards for OBD & Can-Bus, which are closely related.   I think this happened in 1994.  It was TEN years before BMW incorporated full-blown Can-Bus into its motorcycles.  Prior to that, BMW had its own versions of OBD, incorporated into such as the Jetronic & early Motronic systems; primarily for a quite limited number of error or malfunction codes, although there were some other outputs & inputs ....and you'd need the fancy and very pricey BMW dealership machine to do everything possible.

Speed Snoop?
At one time, quite some years ago, the mouthy chat of the media for a short while (they need something to talk about) was that as car computers got sophisticated enough, just about all of them would 'record' certain things, that, if read-out properly, would show the last so-many-seconds of vehicle functions, before some 'event' the deployment of the airbags (soon, I guessed, motorcycle accidents would have this information in their computers too).  Recorded functions would be such as speed, accelerator movement; if the brakes were applied and when, ETC.  Yes, this is not only possible but it IS being done in all cars; has been for some time now, yes, it is TRUE.   Think about what this might mean for motorcyclists.  Gone will be many claims of 'laying it down to avoid an accident', and other such things, which are often not true.  Since both cars and motorcycles will have super-accurate INTERNAL TIME KEEPING CLOCKS, an insurance investigator, or the police investigating an incident, can compare what nearby cars or incident cars, were doing, and you too, on a second by second basis ....and NO camera needed!   Even as I type this, it is pretty much standard in cars, that this sort of 'information' IS AVAILABLE.   Your car's computer WILL, and DOES, record this.

Common slang calls the vehicle computer storage for this a 'snitch box'.

Insurance companies are interested in readouts of this sort of information. So are Authorities, like the police.  Perhaps YOU would be interested in some situations to know exactly what even you did. Sooner or later, it will all be incorporated into just about all motorcycles.  This is NOT pie-in-the sky, it is here NOW on some bikes! IN FACT, it has become relatively popular to have this information constantly available for cars, even by remote radio methods, and it is being promoted by car insurance companies as an accessory FOR WHICH THEY OFFER A DISCOUNT ON YOUR INSURANCE POLICY. Of course, another way of looking at this sort of thing is that everyone who does NOT have such, will have their premiums increase, without notice, specifically. Yep.

The Bus (Buss), somewhat simplified:

An electrical bus is a common interconnection area, point, and/or method of transportation of information or just of moving electricity.  Per wikipedia, in electric power distribution, a busbar (also bus bar, and sometimes misspelled as buss bar or bussbar) is a metallic strip or bar, typically housed inside switchgear, panel boards, and busway enclosures for local high current power distribution.

Very simplified versions, for moving or connecting electricals to common points or nodes, were used in large trucks & in airplanes, all extensively since the early 1930's. Before then, it was commonly used in buildings (and, to a lesser extent in all cars with electrical systems).   In these types of usage a bus was typically just a multiple connection point or perhaps a strip of metal with many connections to it, for a group of common-connected wires.   There might have been more than one such bus, with an interconnection switch (or fuse or automatic circuit breaker) allowing them to be separated, or connected to each other.  Thus, 'systems' in the aircraft or truck, home, office, etc., could be separated, or not.   It was common to have a battery hot bus & a battery ground bus.  This bus idea is done in your HOME, by multiple connections in the power-meter box, for grounds, hots, & neutrals.   The Bus of multiple connections points AND information points or devices is fairly common on even very old equipment.

These uses of Bus (having nothing to do with the BUSS COMPANY, which makes fuses, etc.) are simplified uses of the term.  It gets much more complicated with the usage & meaning today.  A vehicle bus carries a lot of people, so many think that the word was adopted for the modern use of multiple electrical signals that can be on a single wire. An analogy of that thinking might be the TV cable coming into one's home....many dozens or even hundreds of programs on the same single wire.   Although RECORDING status of some things in aircraft and big trucks was quite primitive, and mostly NOT electronic way back in the thirties, it did happen, mechanically.  In some instance an mechanical record was made by electrical means.

In a way one could think of that just mentioned TV cable company's single coaxial cable wire coming into your home as a bus, carrying all those differing TV & audio programs on just one wire, (really two wires, an inner solid wire & the shielding around it). So, warping the use of the term, that could be a signal bus wire.  It is not commonly known that modern cable TV  digital tuner and even recorder, etc...etc....'boxes'...send signals BACK to the Cable Company.  That company no longer likely uses employees climbing power poles to turn your service on/off, and having devices up there that determine what channels, etc.   It is now all done with two-way signals over the coaxial cable.  There are other ways of doing this, without the two way ""conversation"" of digital 'reporting back'.

Today we have a very considerable amount of glass-fiber-optic cable being used. Locally, it is likely being used to the power, TV, phone, etc., 'wiring' to your home, or to a 'node' quite near your home.  This type of cable is capable of carrying a HUGE number of 'channels' of information, SIMULTANEOUSLY.  Fiber optic cables are OFTEN used to interconnect modern all sorts of electronics in your home ....mostly the High Fidelity stereo or home theatre items at present.  In the future, homes will be directly connected by fiber optics to outside the home sources and resources.  That is already being done in large apartment complexes.

In your vehicle, in the electrical system, any particular BUS (there may be many) might be just two (could be more) wires, carrying all sorts of digital or analog coding, from many connected devices. They are shared, differently than with cable tv, but the results are the same.   Digital & occasionally analog coding  with the digital coding moved along in the wiring by synchronized time-related methods, is what separates the functions.  There are far more complicated methods of transmitting data in your vehicle, using a few wires ...but I won't delve deeper into this.

To spell this out a bit differently; a digital bus allows multiple packets of information, from different sources, to travel down one path (possibly of more than one wire), at or near simultaneously; often in a time-sharing method.   Keeping with my explanation of such analogies, the INTERNET is really a bus type system, as information travels in packets ....yes, your E-mail is broken up into many packets; same for website's, etc. transmitted over the Internet, or, World Wide Web.  The internet uses coding & time segments to be sure the needed/wanted information goes to the correct place.  This is VERY similar to OBD & Can-Bus, and the other types described briefly later in this article.

The more recently a car and motorcycle year, the more computerized items, and typically the more SENSORS of various types, that are typically present.  Electronically controlled fuel injection is almost universal now, except for some diesel engines and lawn machinery. Many 'mini' computers are used with many functions & devices.  In some cars, one MAIN computer runs & monitors everything, with maybe some peripheral small computers doing specific things that are not capable by, or for other reasons not inside the main computer.   The TREND for a long time was to greatly increase the number of small computers in a car.  In recent years this has caused innumerable problems with costs, so nowadays the trend is to use less individual computers by expanding the main computer functions and abilities.    I am sure this will continue to be the case. It also means that replacing or rebuilding (if possible) such a computer could be VERY costly.

The first motorcycle to have Can-Bus was probably the Ducati 999 back in 2002.   BMW started it with the R1200 in 2004.   The Classic K-bikes did not have 'real' Can-Bus.

Can-Bus allows most all the various computers (& things that are peripheral, but not a computer) to 'talk' or 'communicate' with each other in both simplified AND complex manners.   This means that NEARLY EVERY electrical device on your bike could be connected to the Can-Bus system, which CONTINUOUSLY & rapidly monitors nearly everything.  Since anything mechanical can be made to produce an electrical signal, EVERYTHING can be monitored and dealt with by the vehicle computer(s) at VERY high speed of information movement.  In many instances the limiting function of some action is how fast a mechanical device will produce a change or force, etc., once it receives the command by the computer to do so.

The system can also monitor current flow, voltage, etc.  If you tried to tap into the electrical system for an extra electrical gadget, Can-bus might complain ....the Can-Bus computer thinks that the bike has a problem.  It might even record the problem, & MIGHT give you a visual signal that all was not well ....the bike might not start ...or otherwise not be rideable.

Some ABS systems talk back & forth with the computer that runs the engine itself.  It is possible for the ABS to thusly have acceleration or other speed conditions or events reported to the ABS computer, & then with other inputs, the bike might have traction control applied.  That is already done on cars & a few BMW bikes ...and will be appearing on more & more bikes in the future.

Problems with CanBus, as far as vehicle owners are concerned, is usually that they cannot connect electrical gadgets, or modify the electrical systems so easily anymore.  We are more likely to be needing a dealership to read codes & find problems using fancy expensive BMW-supplied test equipment; because, when the bike stops running, or has another problem, we will be less likely to be able to fix it ourselves.  You can imagine the costs when the warranty runs out.   It is entirely possible that the systems will be so reliable, that many electrical problems seen in the past will be eliminated.   In MY mind that is a BIG maybe. So far, information tends to show an increased reliability, over-all.  That is to be expected ...especially when the vehicle is new, or nearly new.

We have limited ability to analyze the Classic Jetronic & first two generations of Motronic computers in Classic K bikes, because the recording of sensors is limited.  There will undoubtedly be plenty of experimentation done & ideas & tests posted on various LISTS, Forums, ETC., on the Internet, regarding problems, electrical measurements & for such for all computer equipped bikes.

For now and for the near future, the primary method of adding farkles, etc., to Can-Bus bikes will be an added fuse panel & connections directly to the some add-ons and farkles will contain special Can-Bus compatible circuitry.

DE-sulfating types of battery chargers:
What the heck?
Why do you need to know about battery chargers in a Can-Bus article?

There are Smart chargers that have a so-called "de-sulfating mode".   As far as actually helping the battery, these chargers are generally OK and safe for the battery, if the battery has ~~a quarter charge, or more.   They only work sometimes, and seldom very well.  If the battery charge was quite low for any goodly period of time, these chargers, if they work at all, will be very unlikely to give very much more battery life at all, compared to using a standard charger, or a smart charger without de-sulfation protocols, in trying to resurrect the battery.   Once the sulfation crystals turn into the hard type, the battery is usually toast.

If you use the de-sulfating mode of a charger on a battery that is fully connected to your motorcycle's wiring system, the very high voltage (as much as 25 volt spikes! ...and in some instances, much more of a 'spike' that is very short in time) from the charger CAN INJURE THE BIKE SYSTEMS.   THIS IS PARTICULARLY SO & CAN BE VERY EXPENSIVE for YOU ON CAN-BUS BIKES!  It is potentially bad for the motorcycle even if the ignition key is off.  I highly recommend that you be very prudent & NEVER use de-sulfation MODE on a Can-Bus bike that has the battery installed and fully connected.

If you want to try the de-sulfating mode, DISCONNECT the battery from the motorcycle's wiring!

DO NOT use a desulfation mode with LITHIUM batteries! ...NEVER!!

For another way of looking at Canbus, try this article:

The future,'s where I predict what is going to happen:

The future will continue to be electronics; and, that will accelerate.  It has now been many years since cars got electronic fuel injection & ABS brakes.  GM's ON-STAR two-way communications (with On-Star's ability to do all sorts of things TO your car) was put into its cars.   Now, many cars are being equipped with versions of what ON-STAR does, under various names, & tying it to CAN-Bus/OBDII.   Everything is being integrated.  Your future vehicle will not only record many things, such as your speed, when and how you brake, etc....., but will use GPS to transmit your speed and location to receivers located alongside roads.  Your vehicle ID will be transmitted (license plates are NOT needed, but will likely be kept around for a very long time) will be information of exactly where you are many passengers, their body weight or retina ID (the system will also know WHO was driving, name, address, SS or other number, credit rating, insurance rating, all sorts of things...including speed, recorded in every speed zone, etc.).

OBD/Can-Bus and whatever names will be used, will be welcomed, over-all, by vehicle owners, because of all the sophisticated things they can do, like helping prevent skidding on slippery roads, help with braking, etc. ...but it will be more and more intrusive, reporting your & your vehicle's actions in depth & ways you may hardly believe, and what is in the prior paragraph is only a beginning.   It is likely that your habits (where you park and shop, all sorts of these things) will become fodder for computer data bases about you, and you will get advertisements in strange ways. You will become somewhat more bound-to your vehicle brand dealerships because they have the full diagnostic equipment (which will reprogram your vehicle computers when required).  This ability will tend to remove some of what independent shops are able to do for you, thus help push you to the Dealership.   This will be fought by the Independent repair centers lobbyists, and they will tend to win, only partially.The "Independents" will continue to be with us, for decades to come.  Vehicle manufacturer's will continue to find ways of reducing the use of Independents by vehicle owners.  It will be sometimes effective, at other times not so.

The system of reporting, & retaining customers, advertising, features, etc., will be lumped by industry into a single word:  Telematics.   Vehicle makers will view it as a marketing tool, to improve customer retention rates, for future vehicle purchases, etc. Telematics is happening right now !!!

Besides Big Brother intrusiveness into our lives in countless ways, Telematics will be used by insurance companies, law enforcement organizations, regulators, etc.    It may also be used by thieves, hackers, etc.

Eventually, the OBDII port (a multi-pin plug, usually located under the dashboard) will be eliminated in favor of WIRELESS transmission of data. For the near term, I expect the OBDII port functions MIGHT be only accessible to outside interests upon your approval, already some of that is happening with On-Star, which you may be familiar with in GM cars. I will get into this a bit more in the next section.

This may surprise you.  Here in more depth, is what I wrote about earlier:

You already know that BMW incorporated a small scale computer, or more than one (for ABS), in the Classic K Bikes, & all later models.  The computer runs various functions of the motorcycle & also reports malfunctions by code numbers.  Perhaps you know how to read the codes, or have the proper instrument that does that.   There is a coming change, actually new functions, which will be added to almost all vehicles (cars first, motorcycles eventually).   Perhaps you have heard about Cloud Computing, perhaps in relationship to your personal computer (of whatever type ...portable or not ....).  If your vehicle could 'report' to 'The Cloud' what was going on with your vehicle, whether good or bad, that information could be processed & sent back to a display in your vehicle (& also to the manufacturer & a lot of other places, including "Authorities" and car insurance companies....potentially). Some cars have this now.

Soon some top of the line motorcycles will have projectors of instrument data onto windshields ....of speed, warnings, conditions, fuel, etc.

Manufacturers could send a message to your car or motorcycle computer; to dash display or on the windshield, telling you about some problem needing attention.  Perhaps there was a recall; or, really, almost anything (except, one hopes, advertising!).  How this HAS been put into use INITIALLY is that cars are going to be equipped with MANY MORE monitoring devices in the NEAR future (some happened with GM cars already).  Algorithms will be established for the computer(s) in your vehicle.  LIFE of components will LIKELY be the first thing addressed by this new system.  This is not conjecture ...these things ARE HAPPENING NOW & WILL BE IN ALL VEHICLES, VERY SOON!   I am going to give you some SIMPLE ideas.

Cars are NOW being equipped with very complicated electrical & mechanical monitoring systems & new designs for starter motors, alternators, air conditioners, etc...& almost anything else, that might somehow, affect emissions, fuel mileage, & MANY other things.  Sensors WILL monitor the number of battery starting cycles, temperature of the battery, voltage & capacity of the battery, how long the starter motor was engaged, how fast the battery was recharged, etc.  That information will be transmitted by something like WiFi, to the nearest reception point as you travel.   It is possible it can be cell phone towers, equipped to monitor that frequency band; or, by other means.  Security of communications will be built-in.   When your battery is nearing its calculated end of life, the vehicle's computer will RECEIVE that information, & it will be displayed, somehow.   You can expect monitoring of hundreds of things in your new  vehicle, within a few short years.   MY understanding is that, initially, GM will give you the option of turning on the system for these things, or not.    Privacy could be involved, heavily.  You probably already know that the computer in your car ALREADY will RECORD the speed & some other things, for the last, say, 45 seconds, before the airbags inflate in an accident (or, other reason for the recording, which may be continuous and not need a triggering event).  This computer portion is often called a 'black box', & is often called a 'snitch box' & insurance companies can usually get the information.  This is VERY similar to the data-recording boxes used in Airliners, except yours will not be so environmentally protected.  Thus, in a Court of Law, or in negotiations with insurance companies, THEY could find out what your speed REALLY was, if you used your brakes, and how and when, ETC. In fact, they could probably show what/where road, accurately to a FEW FEET, and MANY more things.  They WILL be able to print-out your ACTUAL driving habits for years/miles/whatever.    YOUR insurance premiums WILL BE based, at least somewhat, on your Car's OWN REPORTING. Further, this sort of measurement and reporting will be tied to YOU in some way, so it will apply to rental cars, rental trucks, wherever you are, at whatever time of day...month...year....etc.   This IS COMING, in even greater depth, in MY opinion.   While the new systems & parts "condition monitoring" is to be a separate add-on, & transmitted & received, I am 100% certain that it will be combined with the existing CanBus/ OBDII, ETC.  Many things will be coming, once this system is fully in-place, such as driverless cars being much more popular; automatic transmittal of breaking of speed laws, & LOTS MORE.  Eventually, NO ONE will be able to operate a vehicle on public roads without his/her IDENTITY known to their...AND NEARBY VEHICLES.  that information WILL BE transmitted to 'the cloud'.  They will find a way to include old vehicles too.  Privacy will be greatly reduced.

To give you an idea of what could EASILY be done, consider this scenario:

You and your girlfriend go for a ride.  The CAR's GPS (separate from any other GPS you know about) knows with 6 feet of where the car was when she got into the car, and the car recorded her weight and that she was in the passenger seat, next to you.  You drove to a restaurant.   The car recorded the distance, and the GPS built into the car knows where the car stopped.....and for how long.   Besides the possibility that the restaurant could have its alcoholic beverage license REQUIRE the recording of your name, age, number of drinks you had, and at what time the drinks were delivered to the table .....the CAR knows when you left.   You went to a nearby pharmacy, where you purchased, for cash, a package of condoms.  That is recorded there, and transmitted by the store to its Cloud site. You then stopped at a 7-11 store and purchased some alcohol.  Yep, recorded. You then stopped at a cannabis store.   In case of a situation where any of this information would be useful to some one, such as a father, lawyer, etc., it is available.  You drive to a favorite spot in the nearby hills.  The car knows your route and destination.  You both got into the rear seat, to, let us say, have some romantic moments.  The car KNOWS you both moved to the rear seat ...and recorded it.   All the information I have mentioned was transmitted, automatically, by the car, to the Internet Cloud.   I could take this further, and have the car measure heart rates, etc.  This might be great for parents wanting to voyeuristically watch over their teens(??)...but, you think this could not happen for you?   You might be very surprised at what your relatively new car knows about YOU, already.  In FACT, ONE of the things newer cars do, is to analyze your driving habits, such as acceleration, braking, etc.,  and then adjust certain aspects of engine control ...and other things....for such as transmission shifting, etc.  These are called Learning Modes, and car repair places deal with re-setting them all the time, during analyzing problems.

This is not overly wild guessing.  MUCH IS ALREADY HERE NOW, built into quite a few cars.   In fact, a very basic 'learning' mode for cars started a long time ago; first with a re-learn mode when the battery was replaced, or went dead and was recharged. Things are being recorded in car computers that are NOT being used (for the most part), such as speed average, speed peak, and it can be permanently in memory. I KNOW that some cars have the capability of looking at stop lights.

Let your imagination have fun.
Don't worry, Big Brother is here to help you!

For the NERDY (& a bit of information about the GS-911 instrument you can purchase NOW):

IN GENERAL, whether the system is CAN-BUS, or, some other type of system, a primary function of these systems was to flag (indicate) problems.  Originally, these systems were designed to give notification to the driver/rider/shop mechanic/ when EMISSIONS would be increased by over 1.5 times the Federal Test Procedure (FTP) limits.   Indications, memory information on problems, & LOTS more, & now-a-days having to do with much more than just emissions, are presently in use.  Note that safety items is also are part of OBDII & nearly every other system used on vehicles.  Various types of ON-BOARD-DIAGNOSTICS are used INDUSTRIALLY for process controls, & very much more ...not hardly just in vehicles.   In the following, I will discuss use of various systems only for VEHICLES, but some are used for industrial purposes as well.

There are quite a few variations of what I have almost generically been calling CAN-Bus and OBDII.  I won't get into them too much here.  CAN-Bus is used for MANY things, not just the main engine computer. Examples for cars & trucks might be such as door functions, climate control, etc.   Regular CAN-Bus itself has limitations.  Its information speed is limited to 1-Mbit/s.   I wrote Mbit/s that way on purpose.   A manufacturer certainly does not want to try to use a CAN-Bus anywhere near its speed limit for information movement, for safety & reliability.   Can-Bus does not work all that well when higher speed real time data is needed, particularly over longer distances in the vehicle.

From this point on to the end of this article it will be a somewhat more nerdy explanation.

One of its limitations is the real-time speed at which data can be moved about.    With Bosch's Can-Bus, the information signal is sent down the wires in 8 byte format.  There is no theoretical limit, at least in the official specification, for a maximum number of information nodes, but, for practical reasons 32 is about the limit.  CanBus is a SERIAL information standard; the specification is complex, but allows for priorities.  Serial means that you can only have one type of information being worked on at any given instant.    While the speed of the processing of information would appear to be very fast & more than capable of most any vehicle function, that is not necessarily so.

As vehicles become much more complicated, such as incorporating things like Collision-Warning Systems, Can-Bus will have, and is, reaching its practical limits.  In some instances, combinations of various methods are used ..... even the use of multiple CAN-Bus systems.

Due to speed & capacity limitations, other protocols have not only been proposed, but are already in use.   A short list of these is:  FlexRay; JASPAR, LIN, SAE J1850, AUTOSAR, MOST, & even the computer FireWire (1394) standard.   MOST, which stands for Media-Oriented-Systems-Transport, is already in wide usage in European cars.   Toyota probably has already begun using a 25 Mbyte/s version of MOST in its Prius.  Yes, 25 mega-BYTES.   MOST in its Revision 3 specifications will allow 150 Mbit/s networks.

FlexRay is already in use on BMW's X5 and 7 series.  FlexRay defines a dual-channel 10 Mbit/s data structure ....and the channels can be used in a redundancy method.  FlexRay is being used by BMW since they are members of a FlexRay Consortium:  BMW, GM, VW, Daimler-Chrysler, Bosch, etc.  FlexRay is much more expensive than Can-Bus, but prices are coming down.

CAN (Can-bus) will likely be THE choice for many vehicle networking nodes for awhile past 2017.  This is my best guess.  CAN works with SAE's J1850 Bus specification, which is widely used with OBDII.   The SAE has various Bus specifications, that is only one of them. That DOES mean that OBD readers MIGHT be able to be used with your BMW motorcycle that has Can-Bus ....but the information, & how to go about using it, has not been widely published.

There are specialty readers that will read the BMW motorcycle information.   The  GS-911 diagnostic tool is available, that 'even you' can purchase.   It reads BMW motorcycle codes, can erase fault codes, etc.  It is VERY versatile in what it can do.  It is available from Ted Porter's Beemershop.

The GS-911 has limited abilities for OLDER BMW motorcycles such as on the Classic K bikes, the K1, K75, K100, K1100.  The following linked page will detail what bikes it works on, and much more:
The following are not covered by the GS-911 instrument:
All motorcycles with mechanical fuel-injection (LE Jetronic) - these are K100, K100LT, K100RS, K100RT, K75, K75c, K75RT, K75s.

Microprocessor Control Units (MCUs) are plentifully used in FlexRay networks.  As more are used, perhaps as ECUs (electronic control units), costs go up, and so does complexity well as capability.  The trend has been towards modular units, each controlling sub-units.

For the ever-so-nerdy, the LIN-bus has the lowest cost per node.  It uses serial interconnections, the maximum speed is 19,200 baud ...and is often used as a CAN sub-bus.

With today's automobiles .....and now motorcycles ....requiring hundreds of megabytes of software code, standards are proposed fairly often.  Just which ones become popular, is the question.  It appears that of the several mentioned above just about all will become standards.

For another way (more visual) of looking at Canbus and computer controllers, try this article:


Initial release 10/17/2009, to K-bmw Internet Mailing List
10/19/2009:  Edited and made into this website article.
10/21/2009:  Added the ADDENDUM.
05/01/2010:  Simplify a bit, and update.
05/21/2011:  Small additions and very minor clarifications and emphasis here and there.
09/22/2012:  QR code, google code, very minor other things.
04/03/2013:  Add link:
01/12/2014:  Add section on the future & revise entire article for clarity & more information.
08/16/2014:  Minor updating.
12/07/2015:  Major addition re: WiFi reporting.
01/18/2016:  Add de-sulfating mode cautions for smart chargers.
01/28/2016:  Meta code updating.  Narrowing article. Horizontal line function changed. Update article.  Increase font size for readability.
05/21/2016:  Final updating on meta's, layout to 100% width, clean up colors/fonts/etc.  Minor clarity improvements.
06/05/2017:  Reduce colors and fonts.
12/11/2017:  Clean up more.  Extensively revise for clarity & later information. Fix margins, colors, fonts, layout.

Copyright, 2017, R. Fleischer

Return to Technical Articles LIST Page

Return to HomePage

Last check/edit: Wednesday, January 17, 2018