1. Measure the wear of the diaphragm spring fingers.
Depth
0.6 mm {0.024 in} max.

2. Measure the flatness of the pressure plate with a straight edge and a feeler gauge.
Maximum clearance 0.5 mm {0.020 in}

3. When checking the diaphragm spring fingers, mount a dial indicator on the cylinder block.
4. Rotate the flywheel and check for misaligned diaphragm spring fingers.
Misalignment
0.6 mm {0.024 in} max.

Clutch unit removal/installation
Clutch disc inspectionMazda 6 Service Manual: Shift Gear (Shifting) Speed Limit
For each gear position while in the manual mode, the speed limit is set as follows:
When the selector lever is operated within the range of the speed limit, the gear
is shifted.
Shift up
The gear does not shift up while the vehicle speed is lower than the speed limit.
Shift down
The gear d ...
Mazda 6 Service Manual: Clutch switch inspection
Note
Perform the following inspection only when directed.
Continuity Inspection
1. Verify that the clutch switch is installed properly.
2. Disconnect the negative battery cable.
3. Remove the clutch switch.
4. Inspect for continuity between the clutch switch terminals using an
ohmmeter. ...