How to Control Door Locks: Step-by-Step Guide
|Did you know? Some GM vehicles allows CAN bus access to open and
AutoPi: Abilities and Features
AutoPi.io is specializing in connected car solutions to securely connect vehicles to the internet and gain data of automotive usage to help car owners improve remote access and control over their vehicle’s functionality.
The AutoPi device not just
allows users to be
connected to the internet, but also to control and create actions via that, like unlocking a car without using a
physical key. Therefore in the following article, we will highlight one example, where the AutoPi device
connects to a Ford Mondeo
For this to work, the bus system through which the doors are controlled, has to be exposed on the OBD port. In our case, with the Ford Mondeo, the following article explains that the door control is achieved on MS-CAN with rate 125kbit/s.
Since the OBD connector on Mondeo MK4 is compatible with the AutoPi (read more about AutoPi CAN-BUS User Guide), it is possible to decode the messages on the AutoPi and replay it.
Build on the information on how to record and play CAN
messages provided on our community
site, the process can be
accomplished by a couple
steps - see below. All of these actions are within the AutoPi cloud management
How To Record and Play
- Once the device is online, go to “Car Explorer”
- In the second step, you
the protocol settings required for your specific make and model. For our model, the
articleexplains the required
However, the description yet fails to give up all the information and details such as payload size (#bits) and data length code (DLC) on our Mondeo MK4 are not provided, therefore an experimental approach is required.
a. Select the bus and protocol you want to use as part of your trial, and then press record. In our case, we have four different MS protocols. Read our CAN Bus sniffer guide for detailed information.
b. Click on test in terminal and adjust the duration of recording to a sensible length. In this example, it lasts for 5 seconds. The trick is to save the file as in the screenshot below where the file is named “unlock1.txt”.
- The device makes a "beep" sound when the
recording begins and
another one when the recording ends. Make sure that the CAN command you want to record is
two sounds (like door unlock).
- If the right protocol settings
applied for the car model you should see hex messages from the CAN bus in your file. Moreover,
now stored on the device and you can play it back immediately using the CAN player on the
right-hand side of
a. If no message is recorded you have to continue with the next protocol settings, and name a new output file e.g. “unlock2.txt”.
- You will see that a lot of
returned from the bus that finds the specific command for your function. We recommend using the
Typically, a lot of the data is repetitions, so you can start out by removing all the
a. Another option is Divide-and-Conquer, i.e. split the file in two using obd play.slice option.If the first part works - great - repeat slicing the identified segment. If the first part did not work try the second part.
- With the filters, narrow down
to as few as possible. Then you can replay the commands one by one and see if you can find the
controlling the function you are looking for.
- When you have found your command you can always resend it by using the obd.play
Alternatively, if the exact hex message is known it is possible to apply obd.send, e.g. obd.send 048#801804092002F0A0 protocol=51 baudrate=125000
Not all vehicles may be that easy to allow door
control by reading the CAN messages and replaying the same content. However it is possible if
is exposed and the reader has an idea which messages are intended for door-specific commands for
Please note that this is an experimental approach and experimenting with your vehicle is at your own risk.