The speedometer indicates the speed of the vehicle.
The display mode can be changed from odometer to trip meter A to trip meter B and then back to odometer by pressing the selector while one of them is displayed. The selected mode will be displayed.

Odometer
The odometer records the total distance the vehicle has been driven.
Trip meter
The trip meter can record the total distance of two trips. One is recorded in trip meter A, and the other is recorded in trip meter B.
For instance, trip meter A can record the distance from the point of origin, and trip meter B can record the distance from where the fuel tank is filled.
When trip meter A is selected, pressing the selector again within one second will change to trip meter B mode.
When trip meter A is selected, TRIP A will be displayed. When trip meter B is selected, TRIP B will be displayed.
The trip meter records the total distance the vehicle is driven until the meter is again reset. Return it to “0.0” by depressing and holding the selector for one second or more. Use this meter to measure trip distances and to compute fuel consumption.
NOTE
Refer to Fuel Economy Monitor.
Meters and Gauges
TachometerMazda 6 Owners Manual: Wheel hub, steering knuckle removal/installation
Caution
Performing the following procedures without first removing the ABS
wheel-speed sensor may possibly cause an open circuit in the harness if it
is pulled by mistake. Before performing the following procedures, remove the
ABS wheel-speed sensor (axle side) and fix it to an appropri ...
Mazda 6 Owners Manual: Information on Passenger Vehicle Tires
Please refer to the sample below.
1. TIN: U.S. DOT tire identification number
2. Passenger car tire
3. Nominal width of tire in millimeters
4. Ratio of height to width (aspect ratio)
5. Radial
6. Run-flat tire
7. Rim diameter code
8. Load index & speed symbol
9. Severe snow conditions ...