The system operates only when the driver is in the vehicle or within operational range while the key is being carried.
Starting the Engine
NOTE
If the vehicle is started and the key is not in the vehicle, the vehicle will not restart after it is shut off and the ignition is switched to off.
With the advanced keyless function

Without the advanced keyless function

NOTE
The engine may not start if the key is placed in the following areas:
Transmitter
Key Suspend FunctionMazda 6 Owners Manual: Gate operator/Canadian Programming
Canadian radio-frequency laws require transmitter signals to “time-out” (or quit)
after several seconds of transmission — which may not be long enough for HomeLink
to pick up the signal during programming. Similar to this Canadian law, some U.S.
gate operators are designed to “time-out ...
Mazda 6 Owners Manual: Front/rear abs wheel-speed sensor inspection
Visual Inspection
Remove the wheel and tire, and inspect the sensor for looseness and damage.
Replace the sensor if necessary.
Clearance Inspection
Inspect the clearance between the wheel-speed sensor and the sensor rotor.
Clearance
0.3-1.1 mm {0.012-0.043 in}
Resistance Inspection
...