CELLULAR COMMUNICATION: SAFETY CONNECT SYSTEM: B1573,B15CB; Short in Telephone Antenna Circuit; 2018 - 2020 MY Sienna [11/2017

Last Modified: 04-05-2023	6.11:8.1.0	Doc ID: RM1000000018IYR
Model Year Start: 2018	Model: Sienna	Prod Date Range: [11/2017 - ]
Title: CELLULAR COMMUNICATION: SAFETY CONNECT SYSTEM: B1573,B15CB; Short in Telephone Antenna Circuit; 2018 - 2020 MY Sienna [11/2017 - ]

DTC

B1573

Short in Telephone Antenna Circuit

DTC

B15CB

Telematics Transceiver Antenna Disconnected

DESCRIPTION

This DTC is set when the DCM (Telematics Transceiver) detects an open or a short in the telephone and GPS antenna assembly circuit. The DCM (Telematics Transceiver) oscillates and receives 824 - 894 MHz or 1850 - 1990 MHz radio-frequency through the telephone antenna assembly.

DTC No.

DTC Detection Condition

Trouble Area

B1573

Telephone antenna assembly impedance is lower than malfunction criterion for 10 seconds when ignition switch is ON.

(Short circuit)

DCM (Telematics Transceiver)
Telephone antenna assembly
Antenna cord sub-assembly
No. 2 antenna cord sub-assembly (roof headlining assembly)
No. 5 antenna cord sub-assembly

B15CB

Telephone antenna assembly impedance is higher than malfunction criterion for 10 seconds when ignition switch is ON.

(Open circuit)

DCM (Telematics Transceiver)
Telephone antenna assembly
Antenna cord sub-assembly
No. 2 antenna cord sub-assembly (roof headlining assembly)
No. 5 antenna cord sub-assembly

HINT:

Refer to "PARTS LOCATION" for the installation location of telephone and GPS antenna cord (See page ).

WIRING DIAGRAM

CAUTION / NOTICE / HINT

HINT:

Before performing this diagnostic procedure, make sure to perform Health Check and confirm that the DCM/VIN registration information is correct.
Click here
Refer to "PARTS LOCATION" for the installation location of telephone and GPS antenna cord.
Click here

PROCEDURE

CHECK DTC

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(d) Perform "HEALTH CHECK" and check for current DTCs (See page ).

Result

Result	Proceed to
DTC B1573 or B15CB is output	A
DTC B1573 or B15CB is not output	B

CHECK FOR INTERMITTENT PROBLEMS

2.	INSPECT TELEPHONE ANTENNA ASSEMBLY

(a) Disconnect the No. 5 antenna cord sub-assembly connector from the telephone and GPS antenna assembly.

*a	Component without harness connected (Telephone Antenna Assembly)

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
4 - 4a	Always	4 to 11 kΩ

REPLACE TELEPHONE ANTENNA ASSEMBLY

3.	INSPECT NO. 5 ANTENNA CORD SUB-ASSEMBLY

(a) Disconnect the No. 5 antenna cord sub-assembly connector from the telephone antenna assembly.

*a	Component without harness connected (No. 5 Antenna Cord Sub-assembly)

(b) Disconnect the No. 5 antenna cord sub-assembly connector from the No. 2 antenna cord sub-assembly.

*a	Component without harness connected (No. 5 Antenna Cord Sub-assembly)

Standard Resistance:

Tester Connection	Condition	Specified Condition
CD-4 - BC-3	Always	Below 1 Ω
CD-4 or BC-3 - Body ground	Always	10 kΩ or higher
CD-4a - BC-3a	Always	Below 1 Ω
CD-4a or BC-3a - Body ground	Always	10 kΩ or higher

REPLACE NO. 5 ANTENNA CORD SUB-ASSEMBLY

4.	INSPECT NO. 2 ANTENNA CORD SUB-ASSEMBLY (ROOF HEADLINING ASSEMBLY)

(a) Disconnect the No. 2 antenna cord sub-assembly (roof headlining assembly) connector from the No. 5 antenna cord sub-assembly.

*a	Component without harness connected (No. 2 Antenna Cord Sub-assembly (roof headlining assembly))

(b) Disconnect the No. 2 antenna cord sub-assembly (roof headlining assembly) connector from the antenna cord sub-assembly (for Antenna Side).

*a	Component without harness connected (No. 2 Antenna Cord Sub-assembly (roof headlining assembly)

Standard Resistance:

Tester Connection	Condition	Specified Condition
BC-3 - AB-3	Always	Below 1 Ω
BC-3 or AB-3 - Body ground	Always	10 kΩ or higher
BC-3a - AB-3a	Always	Below 1 Ω
BC-3a or AB-3a - Body ground	Always	10 kΩ or higher

REPLACE ROOF HEADLINING ASSEMBLY

5.	INSPECT ANTENNA CORD SUB-ASSEMBLY

(a) Disconnect the AB antenna cord sub-assembly connector from the No. 2 antenna cord sub-assembly (roof headlining assembly).

*a	Component without harness connected (Antenna Cord Sub-assembly)

(b) Disconnect the AA antenna cord sub-assembly connector from the DCM (Telematics Transceiver)

*a	Component without harness connected (Antenna Cord Sub-assembly)

Standard Resistance:

Tester Connection	Condition	Specified Condition
AB-3 - AA-1	Always	Below 1 Ω
AB-3 or AA-1 - Body ground	Always	10 kΩ or higher
AB-3a - AA-1a	Always	Below 1 Ω
AB-3a or AA-1a - Body ground	Always	10 kΩ or higher

REPLACE ANTENNA CORD SUB-ASSEMBLY

6.	REPLACE TELEPHONE ANTENNA ASSEMBLY

(a) Replace the telephone antenna assembly with a known good one and check if the same problem occurs again.

Click here

OK:

The system returns to normal.

END

7.	REPLACE DCM (TELEMATICS TRANSCEIVER)

(a) Replace the DCM (Telematics Transceiver) (See page ).

NOTICE:

The ignition switch must be off.
Do not swap the DCM (Telematics Transceiver) with one from another vehicle.

PERFORM DCM ACTIVATION