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27

Ok, before I will answer your specific questions, let's do some introduction on bus systems. It could be that you know parts of these things, but I will start here as people with little or no IT or electronics knowledge should be able to understand this as well. Bus Systems In electronic systems signals are sent from one chip to another using wires (let's ...


15

The CAN buses are primarily separate to manage congestion reduce regulatory concerns over safety-critical systems exert more control over who can access the various buses Simple vehicles will have two CAN buses, one for the engine and safety systems, and one for body controls (lighting, user experience, etc). Complex vehicles will have a separate bus ...


13

It is highly probable that the reason your car was reluctant to start was that the time you were running diagnostics had sapped some of the charge from the battery. The battery on the car will not charge unless the engine is running. It is unlikely that this device would harm your vehicle but it is theoretically (and practically) possible to do temporary ...


8

Everything depends on if the manufacturer multiplexed the windows or not. For example, General Motors tends to multiplex their windows. This means that every door has a module inside it. The module controls the window, door lock, power mirror, etc... and takes inputs from door lock and window switches. The only thing to pass through the door jam is power ...


8

OBD II is a US government mandated diagnostic interface. This interface is guaranteed to provide a specific set of information including but not limited to engine computer data and engine computer trouble codes. When OBD II was rolled out the US government did not force the manufacturers to also standardize the communication interface to the engine ...


8

Sadly you are not going to be able to do what you want simply connecting CAN-H and CAN-L to a serial port. Here is a pointer to the physical interface layer for CANBUS. CANBUS Physical layer ISO 11898 What you will find is that while CAN is a "serial bus" that just means that the data is transmitted one bit at a time. It does not mean that it can be ...


7

To my knowledge there is no way a scanner can cause issues with your computer electronics. This device is a read only device. It doesn't change anything in your computer. It does, however, communicate with the computer. Through this communication it can give the computer commands, such as to clear the codes. This doesn't write anything to the computer, but ...


7

When talking specifically about CAN the answer is none of the above. In a CAN system the nodes do not talk directly to each other, instead the system is message based. Every message has a priority based on its address and that determines who gets to talk. Who ever has the priority message transmits the message to all and who ever needs it reads it in. ...


6

CAN-C is the high speed bus that connects the engine, brakes, airbags etc. CAN-IHS is a low speed bus that connects the comfort systems like radio and climate controls.


6

There is a distinction that needs to be made between: OBD: this is an interface, that specifies the physical and electrical parameters required to connect a diagnostic computer and the car's electronics in a standard way. This is the bit that is mandatory by legal requirement, so that a car manufacturer cannot "lock in" its vehicles by requiring service to ...


6

While this might be a great question for the reverse engineering site that's in beta, I'll give you my take. Hardware Options 1) They make an ODB II <==> UART hardware interface, that will give you serial access to your CAN signals. You can effectively read and write signals to the bus. 2) There are boards like Freescale's SABRE Automotive ...


6

The basics are quite simple. The motor generates a certain torque N and a certain power P at a given RPM. Further more, the relation between power and torque is: P = C * N * RPM where C is a constant to convert all that odd units. For N, P in SI units, it is C = pi / 30 Neglecting any losses, Power is conserved from the motor to the wheels so you ...


6

Did you set the protocol for the chip to monitor on? e.g. ATSP5 for KWP-2000 or ATSP0 for "best guess". What about checking the headers as well - ATH1? I use the following string of commands to monitor my full KWP bus, which is obviously different from CAN, but is similar enough that it might be of use: ATI -- check connection from app to scan tool ATH1 ...


5

My recommendation is that you start with Bosch CAN 2.0 spec, and then move on to openXc, if you have access to a newer Ford vehicle, they provide you with details on how to leverage some CAN interfaces. Another thing to note is that OBD is a standard, but the implementation of CAN is not, different vehicles will have CAN buses wired to different pins on the ...


5

A full CAN message consists of a FRAME ID and a MESSAGE. You're probably going to have to Reverse Engineer the CAN messages to find out which message you want to put on the bus. The answer there also deals with how to read messages as well. As far as specifically addressing the ECU, not sure how you would do that without having the official documentation, ...


5

I've shopped for a rear-vew camera for my car in the past, and one thing you see time and time-again are standard RCA-style video jacks like the picture below from an AliExpress seller: You can easily find other examples by searching for OEM camera kits for cars that had a camera as an option. The cameras all have at least a power plug and an RCA video ...


4

No. The tool in and of itself cannot do any "harm" to the vehicle. If you were testing apps with the engine off, it is quite possible that the battery may have drained to the extent that it gave some hiccups while starting. Low fuel level may also be to blame here. However, If the vehicle has error codes present which are cleared with the tool, the ...


4

The answer would be yes if the vehicle was produced after 2008, otherwise no. in the following article it states it is required as one of the signalling protocols in OBD2 Post 2008. http://en.wikipedia.org/wiki/On-board_diagnostics#OBD-II_signal_protocols So presently vehicles that are currently being produced do have a CAN channel included in the OBD2 ...


4

CAN does not work like you think. CAN is not module based, it is message based. No module speaks directly to any other module. In CAN a module generates a message with an address, that address identifies the data that will be contained in the message. Also the address gives the importance of the message. The lower the address the higher the priority. For ...


4

Every manufacturer is slightly different. With CAN there can be up to 3 different buses. High speed CAN connects things like Engine computer, ABS, air bag computer, Body computer, gauge cluster. This is what is exposed to diagnostic connector under the dash, the DLC. The Body computer or gauge cluster can be used as the gateway between the other buses ...


3

Just grabbing the first 2002 Volvo Replacement Headlamp I could find the headlamps run at 12V/65W, meaning it would draw 5.4A of current. If you hooked up a 1k resistor and ran it straight to ground while the lightbulb was on, that resistor would pull 12mA of current, adding an additional 0.2% load to the battery. From the car's perspective, you'll be ...


3

I was looking for the similar thing and stumbled on a page which describes the protocol for the 650gs. I haven't managed to try it out yet but it seems promising. http://www.f650gs.crossroadz.com.au/Diagnostics.html Topic is discussed here as well: http://f650.com/forum/showthread.php?25550-Diagnostic-plug-pinout-does-anyone-have-it Plese let my know how ...


3

The two requirements are separate. OBDII is required in all vehicles since 1996. This is primarily an emissions related regulation to formalize how vehicles would relay emissions failures to the user and to mechanics. The standard has many parts, but it primarily designated a connector, its pinout, and allowed one of five different electrical signalling ...


3

There are two basic approaches, you can tap a speed sensor directly before it reaches the computer, or use OBD II signals (generated by the computer). Sensors usually generate a voltage, so you have to find the wire you are interested in and then install an analog-to-digital converter. This then has to either go directly to a COM port (if your computer has ...


3

Usually the OBD CAN bus is 'bridged' onto the other CAN buses of the vehicle, in order to facilitate diagnostics of ECUs on the other buses. However, the bridge may only pass diagnostic messages onwards :( It's different on every platform. In terms of the protocol - its a classic reverse engineering problem. You need to capture a few traces of the CAN ...


3

What you are wanting to do is possible. I've had similar experience and desire for my 2010 Camry. From my experience, reading messages from the OBD-II port wasn't getting me anywhere. It was like the CAN messages were only a response to me manually manipulating the the car. I would get a message response from locking or unlocking the doors with the key ...


3

No car has every attribute to be fully autonomous out of the box. Brakes: If a vehicle is equipped with dynamic stability control then software control of the brakes is possible. Dynamic stability control incorporates all the needed pieces to operate the brakes without driver input. The base software will not incorporate software brake control and will ...


2

Even if you connect to the correct bus and broadcast the correct CAN message you still run into the issue, of transmitting a CAN message that is already being transmitted by another ECU. The way CAN works, every can message has an Arbitration ID also referred to as the message id. Under normal operation, no ECU will ever broadcast a message with the same ID ...


2

If I were the guy who designed the electronics, I would make it impossible to do this via CAN-Bus simply because you get bluetooth adapters for OBD2 that someone standing outside the car could pair with and send the unlock instruction to. It's a safety hazard, so I wouldn't support it.


2

I don't think CAN is a necessary part of OBD, it's just the most commonly used system. The OBD requirements are for consistent diagnostics (so that, in theory, any car can be plugged into a standard reader and give a standard set of error codes), wheras CAN is a method for the internal components of the car to communicate (similar in many ways to the USB ...



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