Turbine Speed Sensor: Inspection

Set the ST between the TCM and bulkhead harness.
ST 18460AA040 CHECK BOARD
Set the probe of oscilloscope to the check board connector.
Connector & terminal

No. 12 (+) - No. 42 (-):

Fig 1: Turbine Speed Sensor Connector Terminal
Courtesy of SUBARU OF AMERICA, INC.
Start and warm up the engine.
Check the waveform and output voltage of the turbine speed sensor with engine idling.
NOTE: The waveform cycle changes as the speed changes.

Fig 2: Turbine Speed Sensor Output Voltage Waveform Cycle
Courtesy of SUBARU OF AMERICA, INC.