Move the float to the topmost and bottommost positions, and verify that the resistance between terminals A and B of the unit and the position of the float are as indicated in the figure.

Pid/data monitor and record procedure
Oil pressure switch inspectionMazda 6 Service Manual: Dtc c1955, c1956
Caution
When attaching the tester lead to the DSC HU/CM connector the SST
(49 G066 004) must be used.
Diagnostic procedure
...
Mazda 6 Service Manual: Drive shaft removal/installation
Caution
Performing the following procedures without first removing the ABS
wheel-speed sensor may possibly cause an open circuit in the harness if it
is pulled by mistake. Before performing the following procedures, remove the
ABS wheel-speed sensor (axle side) and fix it to an appropri ...