Mazda 6 Service Manual: Intermittent concern troubleshooting
Vibration Method
1. If malfunction occurs or becomes worse while driving on a rough road or
when engine is vibrating, perform the steps below.
Note
There are several reasons vehicle or engine vibration could cause
an electrical malfunction. Some of the things to check for are:
...
Mazda 6 Service Manual: Immobilizer System
The immobilizer system allows the engine to start only with a key the system
recognizes.
If someone attempts to start the engine with an unrecognized key, the engine
will not start, thereby helping to prevent vehicle theft.
If you have a problem with the immobilizer system or the key, consult ...