Jumper wire
Caution

Voltmeter
is used by connecting the positive (+) probe (red lead wire) to the point where voltage will be measured and the negative (-) probe (black lead wire) to a body ground.

Ohmmeter
Caution

Connectors
Precautions before weldingMazda 6 Service Manual: Underbody Maintenance
Road chemicals and salt used for ice and snow removal and solvents used for dust
control may collect on the underbody. If not removed, they will speed up rusting
and deterioration of such underbody parts as fuel lines, frame, floor pan, and exhaust
system, even though these parts may be coated ...
Mazda 6 Service Manual: Dtc c1148, c1158, c1168, c1178, c1233, c1234, c1235, c1236
Caution
When attaching the tester lead to the ABS (ABS/TCS) HU/CM harness
connector, the SST (49 G066 001) must be used. (See ABS (ABS/TCS) HU/CM
INSPECTION.)
Diagnostic procedure
...