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: Service procedure
Inspection, adjustment
Inspection and adjustment procedures are divided into steps. Important
points regarding the location and contents of the procedures are explained
in detail and shown in the illustrations.
Repair procedure
1. Most repair operations begin with an overview illustr ...
Mazda 6 Owners Manual: Variable air duct (vad) control solenoid valve inspection (l3)
1. Remove the VAD control solenoid valve. (See INTAKE-AIR SYSTEM
REMOVAL/INSTALLATION.)
2. Inspect airflow between the ports under the following conditions.
If not as specified, replace the VAD control solenoid valve.
If as specified, carry out the Circuit Open/Short Inspection.
Circ ...