The tachometer shows engine speed in thousands of revolutions per minute (rpm).
CAUTION
Do not run the engine with the tachometer needle in the RED ZONE. This may cause severe engine damage.

NOTE
When the tachometer needle enters the STRIPED ZONE, this indicates to the driver that the gears should be shifted before entering the RED ZONE.
Speedometer, Odometer, Trip Meter and Trip Meter Selector (Without Multiinformation
Display)
Engine Coolant Temperature Gauge (Without Multi-information Display)Mazda 6 Owners Manual: Driving Tips
WARNING
Do not let the vehicle move in a direction opposite to the direction selected
by the selector lever: Do not let the vehicle move backward with the selector
lever in a forward position, or do not let the vehicle move forward with the selector
lever in the reverse position. Otherwise, t ...
Mazda 6 Owners Manual: Rear door speaker inspection
1. Inspect for resistance between the rear door speaker terminals using an
ohmmeter.
If not as specified, replace the rear door speaker.
2. To verify that the rear door speaker outputs sound, apply voltage to the
rear door speaker and release using a 1.5-V battery.
If not outputs ...