CAN-BUS and OBDII. What is it... why?
What's the future?
What about WiFi in vehicles (for diagnostics!)?
Telematics? Charging cautions!
(with an addendum for the Nerdy about other systems)
© Copyright, 2014, R. Fleischer
Can-Bus is the same as CAN-BUS, CANBUSS, CAN-BUSS, Canbus, CanBus). OBD means On Board Diagnostics. OBDII or OBD2 is the second version, in very common use now.
Can-Bus is a version or type of OBD.
Can-Bus is a method, hardware & software; to enable communications between 'electrical &
electronics things' on your vehicle;
these 'things' can also be mechanical. Can-Bus stands for
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 such as all the varieties of OBDII....all modern cars have such a system; & a diagnostic plug to access it. In a GENERAL sort of way, Can-Bus systems have the ability to transmit information between components at high speed, & to actually make changes in the operation of items. Again, in GENERAL, OBD can do some of that, but mostly it is seen by most as just diagnostic, retaining information in memory, until downloaded for diagnostic work, or such work can include erasing memory, modifying how systems work, etc. But, that is not really true....it can be a serious part of actually operating the vehicle 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;...as only a few wires are needed for most anything. In addition (and more importantly), the ability for the computer(s) to monitor & talk to each other about just about any function, & particularly in a very short time period, 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. There are other reasons, which I will also get into.
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. Perhaps one exception would be the ABS braking system on some of those Classic K bike models. The ABS braking system controlled wheel spin & emergency braking better than
most riders could do manually.
Later bikes than the K1, K75, K100, K1100; sort-of beginning with the K1200, had much fancier systems available.
The ABS system can be modified to include throttle, ignition, & even suspension items, the
result of all these things could be
...and is....stability control systems, & a lot more.....and
these are now STANDARD on many BMW bikes. Braking in corners
is no longer as fearful,
power can be used much better without wheel spin and wheels slipping, ETC...>LOTS OF ETC!
Traction control, stability control, & ABS, all require FAST information processing. Electronics is absolutely necessary for these functions.
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 might cause problems. Typically,
the 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 to the battery.
It is more than even that. Because of how various sensors 'report' to the computer(s),
the battery condition becomes 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
resistance), which would allow Can-Bus and other 'signals' to be disturbed by the
battery condition. This is all fairly simplified compared to what is already being incorporated into new cars...and it will all mostly likely be in motorcycles eventually.
Bosch invented Can-Bus in 1983 for use in Mercedes cars; & actual 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 is OBD-II. A technician can connect a 'reader' (or other perhaps more sophisticated gadget) to an electrical plug in your car or almost all motorcycles since the mid-nineties. He can read out problem codes recorded by the vehicle computer...as 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; later versions are much more sophisticated. The computer(s) provide the information. Information can be real live time, or in memory.
With the some types of 'readers' a technician can actually make adjustments & incorporate vehicle computer updates. Your BMW dealership has sophisticated reading/updating/adjustments computers to analyze and modify your vehicles systems. Modifying the computer functions is called 'flashing'.....as 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 error or malfunction codes, although there were some other outputs & inputs....and you'd need the fancy BMW dealership machine ($18,000.00 I think it used to be, long ago & equivalent to a LOT of $$$ now-a-days) to do everything possible.
At one time there was quite a bit of chit chat, in various media, about the FACT 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' ...like the deployment of the airbags. 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...so, yes, it is TRUE. 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. So are Authorities, like the police. Sooner or later, it will be incorporated into just about all motorcycles. This is NOT pie-in-the sky, it is here NOW on some few bikes!
The Buss (Bus), somewhat simplified: An electrical bus is a common interconnection area, point, and/or method of transportation of information or just electricity.
Very simplified versions were used in large trucks & in airplanes since the 1930's, maybe before. In that type 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 (usually a circuit breaker) allowing them to be separated, or connected to each other. Thus, 'systems' in the aircraft or truck, 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 Buss of multiple connections points AND information points or devices is fairly common on even very old equipment.
These uses of Buss (having nothing to do with the BUSS COMPANY, which makes fuses, etc.) are very simplified uses of the term of buss. 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 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 of programs on the same single wire. In actuality, the word goes way back, when buss, spelled that way, was used. Your dictionary may not show that. 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...kind of exaggerated here, one could think of that just mentioned TV cable company's
single coaxial cable wire coming into your home
as a bus (buss, if you want that spelling), 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. 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. 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 ONE OR TWO (could be more) wires, carrying all sorts of digital or analog codes, from MANY devices connected to just those two wires. Digital (& occasionally analog) coding (digital coding is often moved along in the wiring by TIME related methods) 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 the 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....as 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. 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.
The first motorcycle to have Can-Bus was probably the Ducati 999 back in 2002. BMW started it with the R1200 in 2004. So, 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 most 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...in essence 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. If the load was egregious enough, the bike might not start ...or otherwise be not rideable.
Some ABS systems talk back & forth with the computer that runs the engine itself. It is possible
for the ABS to monitor
acceleration or other speed conditions or events, & then with other inputs,
the bike might have traction control applied.
That is already done on cars & a few 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 we 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 situation when the warranty runs out. Note that 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, the record tends to show an increased reliability, over-all. That is to be expected...especially when the vehicle is new, or nearly new.
We can still analyze (within limits) the Classic Jetronic & first two generations of Motronic computers in Classic K bikes, but it is more of a hassle with the later bikes. 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, etc.
For now, the primary method of adding farkles, etc., to Can-Bus bikes will be an
panel & connections directly to the battery.....plus some few items
containing special Can-Bus
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 de-sulfating mode. These chargers are generally OK for use if the battery has ~~a quarter charge, or more. De-sulfation chargers work sometimes, but if the battery charge was quite low for any goodly period of time, these chargers, IF THEY WORK, 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.
WARNING!!!! If you use the de-sulfating mode of a charger on a battery that is fully
connected to your
bike's wiring system, the very high voltage (as much as 25 volts
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 AND 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 bike! IF you remove the battery from the bike, or at least disconnect it (all wires to the negative terminal will do if careful NOT to connect the charger negative to the bike in any way), then there is NO problem with using a de-sulphating mode charger on ANY bike.
DO NOT use such a charge mode with LITHIUM batteries!...EVER!!
For another way of looking at Canbus, try this article: http://www.bmwra.org/otl/canbus/
The future, ...here's where I predict what is going to happen:
The future will continue to be electronics; and, it will accelerate. It has now been many years since cars got 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).....as will be information of exactly where you are...how many passengers, their body weight or retina ID (the system will know WHO was driving).
OBD/Can-Bus will be welcomed, over-all, by vehicle owners, because of all the sophisticated things it can do, like helping prevent skidding on slippery roads, help with braking, etc....but it will be intrusive, reporting your & your vehicle's actions in depth & ways you may hardly believe. 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, 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; WiFi.
Wifi: This may surprise you.
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 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 vehicle, within a few 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 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). 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 road, where, 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, WiFi 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 the vehicle's computer, with that information transmitted to 'the cloud'. They will find a way to include old vehicles too. Privacy will be greatly reduced.
This is not wild guessing. It IS, 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.
let your imagination have fun...
For the NERDY (but with a bit of information anyone might want...such as on the GS-911 instrument you can purchase):
IN GENERAL, whether the system is CAN-BUS, or, some other type of system, a primary function of the systems ORIGINALLY was to flag 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 & other things, 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 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, because this is megabits, not megabytes. A manufacturer certainly does NOT want to try to use a CAN-Bus anywhere near that speed, 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 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 that processing of information is done 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 reached its practical limits. In some instances, combinations of various methods are used..... and 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.
stands for Media-Oriented-Systems-Transport, is already in wide usage in European
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 until maybe year 2017 or somewhat beyond. 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.
With today's automobiles.....and now motorcycles....requiring hundreds of megabytes
of software code, ....new standards
are proposed fairly often. Just which ones
become popular, is the question. It appears that of the several mentioned
just about all will become standards.
For another way (more visual) of looking at Canbus and computer controllers, try this article: http://www.bmwra.org/otl/canbus/
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: http://www.bmwra.org/otl/canbus/
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.
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Last check/edit: Saturday, May 21, 2016