Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc u1500 keyless uart com. Malfunction

Subaru Legacy BN/BS (2015-2019) Service Manual / Body control system (diagnostics) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc u1500 keyless uart com. Malfunction

1. WITHOUT KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM

DTC DETECTING CONDITION:

• UART between the TPMS & keyless entry CM and the body integrated unit is open or shorted, or has communication failure.

• Communication with TPMS & keyless entry CM is faulty.

Time Needed for Diagnosis:

10 times

TROUBLE SYMPTOM:

Door lock does not operate with keyless.

WIRING DIAGRAM:

NOTE:

For the coupling connector, refer to “WIRING SYSTEM”.

Keyless entry system Keyless Entry System > WIRING DIAGRAM

STEP	CHECK	YES	NO
1.CHECK DTC. 1) Insert the ignition key to the ignition key cylinder and remove. 2) Read the DTC of body integrated unit using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)	Is DTC U1500 displayed- (Current malfunction)	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION
2.CHECK DTC. 1) Turn the ignition switch to OFF. 2) Disconnect the body integrated unit and the TPMS & keyless entry CM connector. 3) Connect the disconnected connectors. 4) Insert the ignition key to the ignition key cylinder and remove. 5) Read the DTC of body integrated unit using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)	Is DTC U1500 displayed- (Current malfunction)	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION
3.CHECK HARNESS (OPEN CIRCUIT). 1) Turn the ignition switch to OFF. 2) Disconnect the body integrated unit and the TPMS & keyless entry CM connector. 3) Using the tester, measure the resistance between terminals. Connector & terminal (i81) No. 10 — (R221) No. 11:	Is the resistance 10 - or less-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION	Repair the open circuit of harness or replace harness.
4.CHECK HARNESS. 1) Turn the ignition switch to ON. 2) Use a tester to measure the voltage between the terminals. Connector & terminal (R221) No. 4 (+) — Chassis ground (−): (R221) No. 6 (+) — Chassis ground (−):	Is the voltage 10 V or more-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION	Repair or replace the open circuit of harness.
5.CHECK HARNESS (OPEN CIRCUIT). 1) Turn the ignition switch to OFF. 2) Using the tester, measure the resistance between terminals. Connector & terminal (R221) No. 5 — Chassis ground:	Is the resistance 10 - or less-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION	Repair or replace the open circuit of harness.
6.CHECK DTC. 1) Connect all the disconnected connectors. 2) Turn the ignition switch to ON. 3) Read the DTC of body integrated unit using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)	Is any DTC other than U1500 displayed-	Replace the body integrated unit. Body Integrated Unit	Replace the TPMS & keyless entry CM. Keyless Entry Control Module > REMOVAL
7.CHECK CONNECTOR. Check for a poor contact between the body integrated unit and the TPMS & keyless entry CM connector.	Is there poor contact of connector-	Repair the connector that has poor contact, or replace harness.	Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again. NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.

2. WITH KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM

DTC DETECTING CONDITION:

• UART between the TPMS CM and the body integrated unit is open or shorted, or has communication failure.

• Communication with TPMS CM is faulty.

Time Needed for Diagnosis:

10 times

TROUBLE SYMPTOM:

Door lock does not operate with keyless.

WIRING DIAGRAM:

NOTE:

For the coupling connector, refer to “WIRING SYSTEM”.

Tire Pressure Monitoring System Tire Pressure Monitoring System > WIRING DIAGRAM

STEP	CHECK	YES	NO
1.CHECK DTC. 1) With the access key in the vehicle, press the push button ignition switch twice without depressing the brake to turn the ignition switch to ON. 2) Read the DTC of body integrated unit using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)	Is DTC U1500 displayed- (Current malfunction)	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION
2.CHECK DTC. 1) Turn the ignition switch to OFF. 2) Disconnect the body integrated unit and the TPMS CM connector. 3) Connect the disconnected connectors. 4) With the access key in the vehicle, press the push button ignition switch twice without depressing the brake to turn the ignition switch to ON. 5) Read the DTC of body integrated unit using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)	Is DTC U1500 displayed- (Current malfunction)	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION
3.CHECK HARNESS (OPEN CIRCUIT). 1) Turn the ignition switch to OFF. 2) Disconnect the body integrated unit and the TPMS CM connector. 3) Using the tester, measure the resistance between terminals. Connector & terminal (i81) No. 10 — (R211) No. 11:	Is the resistance 10 - or less-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION	Repair the open circuit of harness or replace harness.
4.CHECK HARNESS. 1) Turn the ignition switch to ON. 2) Use a tester to measure the voltage between the terminals. Connector & terminal (R211) No. 4 (+) — Chassis ground (−):	Is the voltage 10 V or more-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION	Repair or replace the open circuit of harness.
5.CHECK HARNESS (OPEN CIRCUIT). 1) Turn the ignition switch to OFF. 2) Using the tester, measure the resistance between terminals. Connector & terminal (R211) No. 5 — Chassis ground:	Is the resistance 10 - or less-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC U1500 KEYLESS UART COM. MALFUNCTION	Repair or replace the open circuit of harness.
6.CHECK DTC. 1) Connect all the disconnected connectors. 2) Turn the ignition switch to ON. 3) Read the DTC of body integrated unit using Subaru Select Monitor. Read Diagnostic Trouble Code (DTC)	Is any DTC other than U1500 displayed-	Replace the body integrated unit. Body Integrated Unit	Replace the TPMS CM. Keyless Entry Control Module > REMOVAL
7.CHECK CONNECTOR. Check for a poor contact between the body integrated unit and the TPMS CM connector.	Is there poor contact of connector-	Repair the connector that has poor contact, or replace harness.	Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again. NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.

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