Quote:
Virtyally none of the diagnosic capabilities in modern cars are accessible via OBD-II.
Every manufacturer has proprietary networks built into the car of which OBD-II is a tiny emulation layer. Its designed for emissions testing and emissions related codes, nothing else.
You can't diagnose why your power locks aren't working with it, you can't diagnose why your HVAC controls aren't working. You can't read exhaust gas temperatures, or any other direct sensor outputs. You can't bleed ABS pumps with it, etc, etc, etc.
First, you have to define what you mean about the OBD-II connection. As you state, the OBD-II is used for emissions testing, but there is more on that connection than just the emissions info. I'll call the entire connector the OBD-II connector on the vehicle. There's a lot more available on that connection than most people might think. I know for a fact that Chrysler's J1850 bus system comes out on that connector, as does Ford's. GM cars all so have a connection to the vehicle bus network, but it depends on the vehicle as to what type of bus it is. Several foreign cars have CAN coming out of the connector.
Over the OBD-II connection, I can do all of those things you think cannot be done with your vehicle. Sure, I might not be able to tell you what's causing your power locks to not work, but I can send out a message on the bus to unlock your doors. If they don't unlock, I can check the proper module controlling the door locks. Don't believe me? How do you think ONStar works?All(most) of the OEM sensors are also accessable on the bus, if you monitor the traffic long enough, you can figure out how certain OEM systems work.
I can use the OBD-II connection to open power doors on a certain US automaker's vehicle. I can measure the O2 sensor output. I can determine the Airbag system status. I can turn on and off warning lights on the instrument panel.
It's taken a bit of work to get all these messages down. My job would be a lot easier if they would share some of the messages with me. It doesn't take a long time to figure out how to open the door, but it does take a long time to figure out how to tell where the door is via the communications bus.
Want a good reason why these messages should not *all* be opened up? With them you can reprogram certain OEM functions. I'll not give specific examples here, but think of things that could be disabled which might result in large lawsuit settlements. Most people here should be able to come up with the right idea.
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First, you have to define what you mean about the OBD-II connection. As you state, the OBD-II is used for emissions testing, but there is more on that connection than just the emissions info. I'll call the entire connector the OBD-II connector on the vehicle. There's a lot more available on that connection than most people might think. I know for a fact that Chrysler's J1850 bus system comes out on that connector, as does Ford's. GM cars all so have a connection to the vehicle bus network, but it depends on the vehicle as to what type of bus it is. Several foreign cars have CAN coming out of the connector.
Over the OBD-II connection, I can do all of those things you think cannot be done with your vehicle. Sure, I might not be able to tell you what's causing your power locks to not work, but I can send out a message on the bus to unlock your doors. If they don't unlock, I can check the proper module controlling the door locks. Don't believe me? How do you think ONStar works?All(most) of the OEM sensors are also accessable on the bus, if you monitor the traffic long enough, you can figure out how certain OEM systems work.
I can use the OBD-II connection to open power doors on a certain US automaker's vehicle. I can measure the O2 sensor output. I can determine the Airbag system status. I can turn on and off warning lights on the instrument panel.
It's taken a bit of work to get all these messages down. My job would be a lot easier if they would share some of the messages with me. It doesn't take a long time to figure out how to open the door, but it does take a long time to figure out how to tell where the door is via the communications bus.
Want a good reason why these messages should not *all* be opened up? With them you can reprogram certain OEM functions. I'll not give specific examples here, but think of things that could be disabled which might result in large lawsuit settlements. Most people here should be able to come up with the right idea.