DTC B1500 Keyless UART Com. Malfunction: Wiring Diagram

Keyless entry system. Refer to appropriate SYSTEM WIRING DIAGRAM article.

Fig 1: Keyless Entry System - Wiring Diagram

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Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK DTC. Insert the ignition key to the ignition key cylinder and remove. Read the DTC of body integrated unit using Subaru Select Monitor.	Is B1500 current malfunction?	Go to step 2 .	Go to step 7 .
2 CHECK DTC. Turn the ignition switch to OFF. Disconnect the body integrated unit and keyless entry control module connector. Connect the disconnected connectors. Insert the ignition key to the ignition key cylinder and remove. Read the DTC of body integrated unit using Subaru Select Monitor.	Is B1500 current malfunction?	Go to step 3 .	Go to step 7 .
3 CHECK HARNESS. Turn the ignition switch to OFF. Disconnect the body integrated unit and keyless entry control module connector. Using the tester, measure the resistance between terminals. Connector & terminal With TPMS (i171) No. 11 - (R221) No. 11: Without TPMS (i171) No. 11 - (R345) No. 3:	Is the resistance 10 Ω or less?	Go to step 4 .	Repair the open circuit of harness or replace harness.
4 CHECK HARNESS. Turn the ignition switch to OFF. Use a tester to measure the voltage between the terminals. Connector & terminal With TPMS (R221) No. 6 (+) - Chassis ground (-): Without TPMS (R345) No. 4 (+) - Chassis ground (-):	Is the voltage 10 V or more?	Go to step 5 .	Repair the power supply circuit.
5 CHECK HARNESS. Using the tester, measure the resistance between terminals. Connector & terminal With TPMS (R221) No. 5 - Chassis ground: Without TPMS (R345) No. 7 - Chassis ground:	Is the resistance 10 Ω or less?	Go to step 6 .	Repair the ground circuit.
6 CHECK CONTROL MODULE. Turn the ignition switch to OFF. Remove the keyless entry control module. Install a keyless entry control module that was operating normally on another vehicle.	Does it operate with the remote control key of another vehicle?	Replace the keyless entry control module. Refer to REMOVAL , Keyless Entry Control Module.	Replace the body integrated unit.
7 CHECK CONNECTOR. Check for poor contact of connectors used for UART communication.	Is there poor contact of connector?	Repair the connector that has poor contact, or replace harness.	It is possible that temporary poor communication occurs. Delete the DTC.