Diagnostic procedure
Mazda 6 Service Manual: Locking, Unlocking the Doors
NOTE
The system may not operate if you are too close to the windows or door
handles.
If the key is left in the following areas and you leave the vehicle,
the doors may be locked depending on the radio wave conditions even if the key
is left in the vehicle.
Around the dashboard
...
Mazda 6 Service Manual: Mechanical system test
Mechanical System Test Preparation
1. Engage the parking brake and use wheel chocks at the front and rear of the
wheels.
2. Inspect the engine coolant. (See ENGINE COOLANT LEVEL INSPECTION.)
3. Inspect the engine oil. (See ENGINE OIL INSPECTION.)
4. Inspect the ATF levels. (See AUTOMATIC TRANS ...