DTC U1720: Lost Communication With Integrated Starter Generator: Wiring Diagram

WARNING: This page is about a different car, the 2015 Subaru XV Crosstrek. However, it is still accessible from the selected car via links, so may be relevant.

Hybrid system < Ref. to WIRING DIAGRAM , Hybrid Electric Vehicle System.>

Fig 1: Lost Communication With Integrated Starter Generator - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

DTC PROCEDURE

Step	Check	Yes	No
1 CHECK BATTERY. Check the 12 volt engine restart battery.	Is the condition normal?	Go to step 2 .	Replace or charge the battery.
2 CHECK CONNECTOR. Check the integrated starter generator connector (E163).	Is there looseness or poor contact of connector?	Repair the connector.	Go to step 3 .
3 CHECK HARNESS (SHORT TO GROUND). Turn the ignition switch to OFF. Disconnect the HPCM connector. Disconnect the integrated starter generator connector. Using a tester, measure the resistance between HPCM connector and chassis ground. Connector & terminal (B605) No. 4 - Chassis ground:	Is the resistance 1 MΩ or more?	Go to step 4 .	Repair ground short circuit of harness between the HPCM connector and the integrated starter generator connector.
4 CHECK HARNESS (SHORT TO POWER). Using a tester, measure the voltage between the HPCM connector and chassis ground. Connector & terminal (B605) No. 4 (+) - Chassis ground (-):	Is the voltage less than 1 V?	Go to step 5 .	Repair the short circuit to power in harness between the HPCM connector and the integrated starter generator connector.
5 CHECK HARNESS (OPEN CIRCUIT). Using a tester, measure the resistance between the HPCM connector and integrated starter generator connector. Connector & terminal (B605) No. 4 - (E163) No. 4: (B605) No. 5 - (E163) No. 5:	Is the resistance less than 1 Ω?	Replace the integrated starter generator. < Ref. to INTEGRATED STARTER GENERATOR (ISG) .>	Repair the open circuit of the harness between the HPCM connector and the integrated starter generator connector.