1. Verify that the joint shaft is not twisted or cracked.
2. Turn the joint shaft by hand and verify that the bearing rotates smoothly and freely.

Drive shaft
Joint shaft removal/installationMazda 6 Service Manual: Ignition switch inspection
1. Disconnect the negative battery cable.
2. Remove the column cover. (See COLUMN COVER REMOVAL/INSTALLATION)
3. Disconnect the ignition switch connectors.
4. Inspect for continuity between the ignition switch terminals using an
ohmmeter.
If not as specified, replace the ignition switch.
...
Mazda 6 Service Manual: Coil removal/installation
Note
Do not remove the coil unless you are replacing it.
When only the coil is replaced, the immobilizer system reprogram
procedure is not necessary.
1. Disconnect the negative battery cable.
2. Remove the column cover.
3. Remove in the order indicated in the table.
4. Install in ...