OBDLink update v2.1.0 changed the default device baud rate from 38400 to 115200 baud,
in order to help increase the sampling rate for Bluetooth and WiFi units. If
you own an OBDLink scan tool with a Bluetooth option, and attempt to upgrade
it to v2.1.0, you must also separately change the communication baud rate of
the built-in Bluetooth module.
After you upgrade the firmware via USB or Bluetooth, perform the following
steps to change the baud rate of the Bluetooth module:
- Connect the scan tool to the vehicle, and check to make sure that the "STATUS"
light is rapidly alternating between red and amber colors. Leave the USB cable unplugged. If the light is not changing colors, power cycle the scantool.
- If not already done, pair with the Bluetooth module (refer to the Bluetooth
Quick Start Guide if you're not sure how).
- Connect to the Bluetooth module using your favorite terminal program. Be sure to use a terminal that does not use 'Send' button, but instead transmits each character as it's typed (e.g. HyperTerminal, TeraTerm).
- At this point, the "STATUS" LED must be green. If not, make sure the device has been properly paired and the correct Outgoing Bluetooth COM port has been selected in the terminal program.
- Close connection in the terminal, leaving the program running: Call menu, Disconnect in HyperTerminal; File menu, Disconnect in TeraTerm.
- Power cycle the scan tool by unplugging the OBD cable and plugging it back in. Ensure that the "STATUS"
light is rapidly alternating between red and amber colors. If not, power cycle the scantool again.
- Reopen the connection in the terminal: Call menu, Call in HyperTerminal; File Menu, New Connection in TeraTerm.
You must perform step 8 within 60 seconds of power cycling the OBDLink (step 6).
- Send $$$ command. Be sure the three '$' characters are sent in quick succession and there is no more than a second delay between each. Do not press 'Enter' after this command. You should see the Bluetooth module respond with CMD and the "STATUS" LED start rapidly blinking green.
- Send the following commands with no spaces between characters, pressing 'Enter' after each. Unless local echo is enabled, you will not see the command characters as you type. However, if successful, the module will respond with AOK after the first two commands and Reboot! after the last one.
You should now be able to connect via Bluetooth at the new baud rate.
Problem: I updated the scan tool firmware to v2.1.0, but couldn't
switch the Bluetooth module to the new baud rate.
Solution: Revert the firmware to version 2.0.2. You must be connected to the scan tool via USB in order to be able
to do this.
Problem: I need to switch the baud rate of the Bluetooth module
back to 38400.
Solution: follow the steps for changing the baud rate, but replace the
su, 11 command with su, 38