Wiring Diagram:

Fig 1: Wiring Diagram - DTC P0607 Control Module Performance

Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE (DTC P0607)

Step	Check	Yes	No
1 CHECK INPUT VOLTAGE OF ECM. Turn the ignition switch to ON. Measure the voltage between ECM connector and chassis ground. Connector & terminal (B135) No. 5 (+) - Chassis ground (-): (B135) No. 6 (+) - Chassis ground (-):	Is the voltage 10 - 13 V?	Go to step 2.	Repair the open or ground short circuit of power supply circuit.
2 CHECK INPUT VOLTAGE OF ECM. Start the engine. Measure the voltage between ECM connector and chassis ground. Connector & terminal (B135) No. 5 (+) - Chassis ground (-): (B135) No. 6 (+) - Chassis ground (-):	Is the voltage 13 - 15 V?	Go to step 3.	Repair the open or ground short circuit of power supply circuit.
3 CHECK ECM GROUND HARNESS. Measure the voltage between ECM connector and chassis ground. Connector & terminal (B137) No. 1 (+) - Chassis ground (-): (B137) No. 2 (+) - Chassis ground (-):	Is the voltage less than 1 V?	Repair the poor contact in ECM connector. Replace the ECM if defective. < Ref. to ENGINE CONTROL MODULE (ECM) . >	Further tighten the engine ground terminal.