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: Discharge headlight service warnings
Discharge headlight bulb service warnings
To prevent electrical shock when replacing the discharge headlight bulb,
dry hands thoroughly, and carry out work in an area out of rain.
When the light switch is on, approx. 25,000 V of high voltage passes
through the discharge headlight bulb so ...
Mazda 6 Service Manual: Intake air temperature (iat) sensor inspection
Resistance Inspection
Note
Perform the following inspection only when directed.
1. Disconnect MAF/IAT sensor.
2. Measure the resistance between the MAF/IAT sensor terminals D and E using
an ohmmeter.
If not as specified, replace the MAF/IAT sensor.
If the MAF/IAT sensor is okay, but ...