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Difference between OBDII and CAN

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 ...
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20 votes

Can a vehicle be harmed with bad inputs via an OBD-2 port?

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 ...
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17 votes
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Why are there multiple CAN buses in vehicles?

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 ...
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9 votes

Can a vehicle be harmed with bad inputs via an OBD-2 port?

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 ...
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9 votes
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Is it possible to auto close the power window of a car using OBD and CAN bus?

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 ...
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9 votes

Difference between OBDII and CAN

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 ...
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8 votes

Why are there multiple CAN buses in vehicles?

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 ...
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8 votes

ATMA on OBDII not Working

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 ...
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8 votes
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Is there a way to use a PC as an ECU for testing CANBUS Sniffer devices?

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 ...
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7 votes
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What is the difference between CAN-C and CAN-IHS buses?

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.
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7 votes
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Controlling door lock/unlock via CAN bus

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 ...
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7 votes

About heavy-duty vehicle diagnostic port

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. ...
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6 votes

Since when is CAN bus mandatory for new vehicles?

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 ...
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6 votes

Can a vehicle be harmed with bad inputs via an OBD-2 port?

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 ...
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6 votes
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Computing Wheel Torque From Engine Torque

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 ...
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5 votes

How to control a car (accelerating, braking, steering) programmatically?

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 ...
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5 votes

Received frames from vehicles with multiple ECU chips

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 ...
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5 votes

Can a vehicle be harmed with bad inputs via an OBD-2 port?

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,...
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OBD or CAN - what's mandatory (EU and US)

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 ...
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5 votes
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Can I turn the steering wheel in Honda Civic 2017 (No Honda Sending) by sending commands via CAN bus (OBD ii port)?

No not directly through the OBDII port. There is no way of sending steering activations through OBD even with dealer level diagnostic equipment. Imagine the safety implications if this was possible. ...
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4 votes

Read vehicle speed data in real time

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 ...
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4 votes

Received frames from vehicles with multiple ECU chips

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 ...
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4 votes

How is video transmitted in the car? (E.g., from backup camera to NAV display.)

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 ...
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4 votes

Is it possible to access multiple CAN buses through the OBD-II port?

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. ...
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4 votes
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Is it possible to access multiple CAN buses through the OBD-II port?

I figured it out. The answer is manufacturer dependent. The OBD-II diagnostic port has a number of pins which are listed as "Vendor Option". The manufacturer may choose to connect one or more of these ...
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4 votes

OBD-II Mode and PIDs specifically used for Electric vehicles?

It seems like every (lots of people on this forum) one is mixing up what OBD is and what CAN is. OBDII is a standard ratified in 1996 in the US. This standard is required by the government and ...
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4 votes

Sniffing the CANbus on an Audi A5

I don't see how this is different from your previous question. No data is actively sent to the OBD port on late VAG vehicles as this in connected to a gateway and only responds to PIDs and ...
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4 votes
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Why modern car networks are known as "unsafe"?

In an ideal world, you are right, the entertainment system should be entirely separate from engine management, navigation, locks, immobiliser etc. But the world isn't ideal, and many decisions are ...
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3 votes
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CanBus - monitoring

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 ...
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3 votes
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Can steering be electrically controlled?

Today, we don't only have cruise control. We also have cars which can park the car automatically in a parking spot. The driver just sits there and monitors the car, may be, he is responsible for gas ...
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