CELLULAR COMMUNICATION: SAFETY CONNECT SYSTEM (for Sedan, Gasoline Model): B1573,B15CB; Short in Telephone Antenna Circuit; 2020 MY Corolla Corolla Hatchback GR Corolla [09/2019

Last Modified: 07-31-2024	6.11:8.1.0	Doc ID: RM100000001LF5N
Model Year Start: 2020	Model: GR Corolla	Prod Date Range: [09/2019 - 04/2020]
Title: CELLULAR COMMUNICATION: SAFETY CONNECT SYSTEM (for Sedan, Gasoline Model): B1573,B15CB; Short in Telephone Antenna Circuit; 2020 MY Corolla Corolla Hatchback GR Corolla [09/2019 - 04/2020]

DTC

B1573

Short in Telephone Antenna Circuit

DTC

B15CB

Telematics Transceiver Antenna Disconnected

DESCRIPTION

These DTCs are stored when the DCM (Telematics Transceiver) detects an open or a short in the telephone and GPS antenna assembly (for Roof Side) circuit. The DCM (Telematics Transceiver) oscillates and receives 824 - 894 MHz or 1850 - 1990 MHz radio-frequency through the telephone and GPS antenna assembly (for Roof Side).

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B1573

Short in Telephone Antenna Circuit

Telephone and GPS antenna assembly (for Roof Side) impedance is lower than malfunction criterion for 10 seconds when engine switch is on (IG).

(Short circuit)

DCM (Telematics Transceiver)
Telephone and GPS antenna assembly (for Roof Side)
Telephone and GPS antenna cord (Antenna cord sub-assembly (for Type A))
Telephone and GPS antenna cord (Antenna cord sub-assembly (for Type B))
Telephone and GPS antenna cord (No. 2 antenna cord sub-assembly)

B15CB

Telematics Transceiver Antenna Disconnected

Telephone and GPS antenna assembly (for Roof Side) impedance is higher than malfunction criterion for 10 seconds when engine switch is on (IG).

(Open circuit)

DCM (Telematics Transceiver)
Telephone and GPS antenna assembly (for Roof Side)
Telephone and GPS antenna cord (Antenna cord sub-assembly (for Type A))
Telephone and GPS antenna cord (Antenna cord sub-assembly (for Type B))
Telephone and GPS antenna cord (No. 2 antenna cord sub-assembly)

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 engine switch off.

(b) Connect the Techstream to the DLC3.

(d) Turn the Techstream on.

(e) Clear the DTCs.

Body Electrical > Telematics > Clear DTCs

(f) Recheck for DTCs.

Body Electrical > Telematics > Trouble Codes

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 AND GPS ANTENNA ASSEMBLY (for Roof Side)

(a) Disconnect the telephone and GPS antenna assembly (for Roof Side) connector.

*a	Component without harness connected (Telephone and GPS Antenna Assembly (for Roof Side))

(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 AND GPS ANTENNA ASSEMBLY (for Roof Side)

3.	INSPECT ANTENNA CORD SUB-ASSEMBLY (ANTENNA CORD SUB-ASSEMBLY (for Type B))

(a) Disconnect the I telephone and GPS antenna cord (antenna cord sub-assembly (for Type B)) connector.

*a	Component without harness connected (Telephone and GPS Antenna Cord (Antenna Cord Sub-assembly (for Type B)))

(b) Disconnect the H telephone and GPS antenna cord (antenna cord sub-assembly (for Type B)) connector.

*a	Component without harness connected (Telephone and GPS Antenna Cord (Antenna Cord Sub-assembly (for Type B)))

Standard Resistance:

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

REPLACE TELEPHONE AND GPS ANTENNA CORD (ANTENNA CORD SUB-ASSEMBLY (for Type B))

4.	INSPECT TELEPHONE AND GPS ANTENNA CORD (ANTENNA CORD SUB-ASSEMBLY (for Type A))

(a) Disconnect the G telephone and GPS antenna cord (antenna cord sub-assembly (for Type A)) connector.

*a	Component without harness connected (Telephone and GPS Antenna Cord (Antenna Cord Sub-assembly (for Type A)))

(b) Disconnect the F telephone and GPS antenna cord (antenna cord sub-assembly (for Type A)) connector.

*a	Component without harness connected (Telephone and GPS Antenna Cord (Antenna Cord Sub-assembly (for Type A)))

Standard Resistance:

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

REPLACE TELEPHONE AND GPS ANTENNA CORD (ANTENNA CORD SUB-ASSEMBLY (for Type A))

5.	INSPECT TELEPHONE AND GPS ANTENNA CORD (NO. 2 ANTENNA CORD SUB-ASSEMBLY)

(a) Disconnect the E telephone and GPS antenna cord (No. 2 antenna cord sub-assembly) connector.

*a	Component without harness connected (Telephone and GPS Antenna Cord (No. 2 Antenna Cord Sub-assembly))

(b) Disconnect the C telephone and GPS antenna cord (No. 2 antenna cord sub-assembly) connector.

*a	Component without harness connected (Telephone and GPS Antenna Cord (No. 2 Antenna Cord Sub-assembly))

Standard Resistance:

Tester Connection	Condition	Specified Condition
E-1 - C-1	Always	Below 1 Ω
E-1 or C-1 - Body ground	Always	10 kΩ or higher
E-1a - C-1a	Always	Below 1 Ω
E-1a or C-1a - Body ground	Always	10 kΩ or higher

REPLACE TELEPHONE AND GPS ANTENNA CORD (NO. 2 ANTENNA CORD SUB-ASSEMBLY)

6.	REPLACE TELEPHONE AND GPS ANTENNA ASSEMBLY (for Roof Side)

(a) Replace the telephone and GPS antenna assembly (for Roof Side) 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).

Click here

NOTICE:

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

PERFORM DCM ACTIVATION