FastMileage: OBDII Connector

FastMileage can use a separately purchased OBDII adapter that connects via bluetooth. FastMileage can log Trips automatically using this adapter. Note that your vehicle must support specific OBDII request types to work properly with FastMileage.

What is an OBDII adapter?
All light duty vehicles produced for the American and Canadian market, since 1995, have an OBDII port that connects to the engine computer. An OBDII adapter enables another computer (IE, your smartphone) to read your vehicle's information.

Where can I get an OBDII adapter?
Do an internet search for "ELM327 Bluetooth" to locate examples. You can purchase these on Amazon or eBay.

Which Bluetooth Adapter?
Some inexpensive adapters do not work with FastMileage (and may not work at all). A random sample of $5.00-$20.00 adapters on Amazon resulted in 5 nonworking, and one working.

We have sucessfully tested OBDLink LX (see

You can test your adapter by using the Torque app ( ). If it works with Torque, it will probably work with FastMileage.

Testing FastMileage with your Vehicle

  • First, test your vehicle and OBDII adapter with another app like Torque. Check to see that Torque displays your vehicle's RPM gage correctly.
  • Next, in FastMileage, check the box next to Menu/Use Bluetooth for OBDII.
  • Click Bluetooth Devices and select the paired device.
  • Click Auto-Start/Stop Trip with OBD and select either Check for car when screen turns on or Check for Car Automatically.
  • On the FastMileage main screen, touch the box that shows Driver, Vehicle, and Odometer. Enter the information where requested. The odometer is the current Odometer value from your vehicle.
  • If you start your car, a trip should start within a few seconds (you may need to turn your screen OFF then ON again if you have set Check for car when screen turns on).

Odometer and OBDII
There is no exact Odometer reading available from your car's computer.

The Odometer value available in your vehicle's computer is a value that represents the number of Kilometers since error codes were cleared. This value is always in kilometers (even if your vehicle displays miles) and only goes from 0 to 65,535 KM-- approximately 0 to 40,630 Miles.

This value is not available on all cars. (If it is not available, your FastMileage Trip mileage will not increase and you will have to edit your trips to set the mileage).

Note that the number of Kilometers since error codes were cleared does not give you exact distances down to the tenths of a mile or kilometer. If you drive short distances, you may see trips with 0.0 Miles and then a trip with 0.6 Miles.

Auto-start Trips- Battery Usage
You can choose to have FastMileage check for your trip start only when the screen is turned on (which happens when you plug your phone into a car charger, for example). This option saves battery power but you will need to ensure that you always click the "on" button or plug in a charger prior to a trip. Trip stop is automatic- you don't need to turn on the screen at the end of a trip.

If you choose Check for car automatically, FastMileage will check for your vehicle periodically and automatically start and stop trips. This option will use more battery power.

Setting the Odometer with OBDII
After you have set up the OBDII connector, enter the Odometer reading into the Current Odometer value. Check it periodically to ensure that FastMileage is updating the Odometer properly on your trips. Once the number of Kilometers since error codes were cleared reaches 65,535 KM the Trip Odometer will not update until you have a Check Engine code and have it reset.