Crankshaft Position Sensor

Disconnect the ground terminal from battery sensor. Ref. to BATTERY
Prepare an oscilloscope.
While pressing the section (A) shown in the figure, move the lock lever (B) in the direction of the arrow to disconnect the connectors from the ECM in numerical order as shown in the figure.

Fig 1: Moving Lock Lever
Courtesy of SUBARU OF AMERICA, INC.
Attach the ST between the ECM, engine harness and the bulkhead wiring harness. Ref. to CAUTION , General Description.
ST 18460AA050 CHECK BOARD

Connect the probe to ST.

Fig 2: Connecting Probe To ST

Courtesy of SUBARU OF AMERICA, INC.

Terminal No.	Probe
40	+
27	-

Start the engine and let it idle.
Check the waveforms and voltage.
NOTE: For waveform and voltage, proceed to "Engine Control Module (ECM) I/O Signal". Ref. to ELECTRICAL SPECIFICATION , Engine Control Module (ECM) I/O Signal.
After inspection, install the related parts in the reverse order of removal.