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39

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 ...


20

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 ...


17

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 for ...


9

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 ...


9

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 ...


9

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

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 --...


8

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. ...


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

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 Infotainment,...


7

Isn't it a standard, so all vehicles are wired the same (for a given connector)? The following information comes from the Handbook of hardware schemes, cables layouts and connectors pinouts website. Here is the SAE J1708 9-pin connector. H,J are not connected. A and B are twisted in cable. C and D are twisted in cable. F and G are twisted in cable. SAE ...


6

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 ...


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

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

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 can ...


6

The OBD-II port supports a number of electrical protocols, but all of them are serial in nature. There is nothing you can do to any of the OBD-II pins with "plain negative pulses" to do what you want to do. One path to what you want is a cheap ELM327 device sold by just about everyone on Amazon.com. They are very inexpensive and easy to use. If you get one ...


5

Just this morning I connected an ELM327 to a '05 Volvo XC90. After only 1km, the message was displayed for "Anti-skid service required", and then "Anti-skid temporarily unavailable". I removed the ELM, and went home, and checked the car on the laptop based Volvo VIDA/DICE. This showed a BCM fault, CAN network communication error with SAS (steering angle ...


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

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 ...


5

If your vehicle is 2008 or newer it is using the can protocol, you can use the AT CR command to select which ECU you want to hear from. Here's how: send AT H1 this will turn on headers to see the addresses of the ECU's. send 0100 this is an OBD command to show which of the pids from 1-20 are supported. your response should be like: 7E8064100BE3EA813 ...


5

I believe you are confusing CAN and OBD. CAN is an electronics interface protocol. Short for Controller Area Network, CAN allows for expandable interconnected systems, so you can add new sensors and actuators to a network with relative ease. It is comparable to SPI and I2C networking protocols. It makes sense that few automotive manufacturers would want to ...


4

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 ...


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

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 ...


4

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 - it's a classic reverse engineering problem. You need to capture a few traces of the CAN ...


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

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 ...


4

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

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 and ...


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