Toyota Avalon (XX50): Extension Module Disconnected 2 (B1543). HD Radio Tuner Malfunction (B1551,B158D,B15A0,B15B0,B15B3,B15B7,B15BA,B15F9). Extension Module Malfunction 2 (B1556)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Audio, Visual, Telematics / Navigation / Multi Info Display / Navigation System(for Gasoline Model) / Extension Module Disconnected 2 (B1543). HD Radio Tuner Malfunction (B1551,B158D,B15A0,B15B0,B15B3,B15B7,B15BA,B15F9). Extension Module Malfunction 2 (B1556)

Extension Module Disconnected 2 (B1543)

DESCRIPTION

If the radio and display receiver assembly cannot detect the navigation ECU for a certain period of time (90 seconds) after the engine switch is turned on (ACC) and the radio and display receiver assembly confirms that the information is missing by checking past navigation ECU recognition information (registered information), this DTC will be stored.

HINT:

The Navigation system uses USB communication between devices. If an open, short, short to +B or short to ground occurs in the USB circuit, communication is interrupted and the Navigation system will not operate normally.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B1543

Extension Module Disconnected 2

Navigation ECU disconnected
  • Navigation ECU
  • Radio and display receiver assembly
  • Harness or connector

HINT:

This DTC may be stored due to environmental reasons such as electrical noise or interference.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Depending on the parts that are replaced during vehicle inspection or maintenance, performing initialization, registration or calibration may be needed. Refer to Precaution for Navigation System.

    Click here

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • When replacing the radio and display receiver assembly or navigation ECU, always replace it with a new one. If a radio and display receiver assembly or navigation ECU which was installed to another vehicle is used, the following may occur:
    • A communication malfunction DTC may be stored.
    • The radio and display receiver assembly or navigation ECU may not operate normally.

PROCEDURE

1.

CHECK MAP SCREEN

(a) Turn the engine switch on (ACC) and wait for 90 seconds.

(b) Press the "MAP" switch and check that the map screen is displayed normally.

Result

Proceed to

Map screen is displayed normally

A

Map screen is not displayed normally

B

HINT:

  • This DTC may be stored due to environmental reasons such as electrical noise or interference.
  • Clear past DTCs when the map screen is displayed normally. (Codes stored due to past environmental factors)
A

USE SIMULATION METHOD TO CHECK

B

2.

CHECK DTC

(a) Clear the DTCs.

Body Electrical > Navigation System > Clear DTCs

(b) Turn the engine switch off.

(c) Turn the engine switch on (IG) and wait for 90 seconds.

(d) Recheck for DTCs and check that no DTCs are output.

Body Electrical > Navigation System > Trouble Codes

OK:

No DTCs are output.

OK

USE SIMULATION METHOD TO CHECK

NG

3.

CHECK HARNESS AND CONNECTOR (NAVIGATION ECU - BATTERY AND BODY GROUND)

(a) Disconnect the G13 navigation ECU connector.

*a

Front view of wire harness connector

(to Navigation ECU)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

G13-23 (GND) - Body ground

Always

Below 1 Ω

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

G13-10 (+B) - Body ground

Always

11 to 14 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

CHECK HARNESS AND CONNECTOR (RADIO AND DISPLAY RECEIVER ASSEMBLY - NAVIGATION ECU)

(a) Disconnect the G109 navigation ECU connector.

*a

Front view of wire harness connector

(to Radio and Display Receiver Assembly)

*b

Front view of wire harness connector

(to Navigation ECU)

(b) Disconnect the G111 radio and display receiver assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

G109-4 (US4+) - G111-1 (US4+)

Always

Below 1 Ω

G109-5 (US4-) - G111-2 (US4-)

Always

Below 1 Ω

G109-6 (UGD4) - G111-3 (UGD4)

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

REPLACE NAVIGATION ECU

(a) Replace the navigation ECU with a new one.

Click here

NEXT

6.

CHECK DTC

(a) Clear the DTCs.

Body Electrical > Navigation System > Clear DTCs

(b) Turn the engine switch off.

(c) Turn the engine switch on (IG) and wait for 90 seconds.

(d) Recheck for DTCs and check that no DTCs are output.

Body Electrical > Navigation System > Trouble Codes

OK:

No DTCs are output.

OK

END (NAVIGATION ECU IS DEFECTIVE)
NG

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

HD Radio Tuner Malfunction (B1551,B158D,B15A0,B15B0,B15B3,B15B7,B15BA,B15F9)

DESCRIPTION

These DTCs are stored when a malfunction occurs in the radio and display receiver assembly.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B1551

HD Radio Tuner Malfunction

When any of the following conditions is met:

  • "HD Radio" tuner decorder malfunction
  • "HD Radio" tuner audio output section malfunction
  • "HD Radio" tuner decorder RF/IF malfunction

Radio and display receiver assembly

B158D

Video Signal Stoppage

The internal video signal of the radio and display receiver assembly is interrupted

Radio and display receiver assembly

B15A0

LAN Master Malfunction

When either of the following conditions is met:

  • Bus malfunction
  • EEPROM error

Radio and display receiver assembly

B15B0

Display Screen Malfunction

Picture circuit (TFT unit) malfunction

Radio and display receiver assembly

B15B3

Radio Tuner Malfunction

When any of the following conditions is met:

  • AM tuner PLL is unlocked
  • FM tuner PLL is unlocked
  • Tuner malfunction

Radio and display receiver assembly

B15B7

Bluetooth Module Malfunction

"Bluetooth" module malfunction

Radio and display receiver assembly

B15BA

XM Tuner Malfunction

When either condition below is met:

  • Internal IC malfunction
  • Tuner malfunction

Radio and display receiver assembly

B15F9

UART Communication Malfunction(for A/C)

When either of the following conditions is met:

  • Open in UART communication line is detected during radio and display receiver assembly startup routine
  • Open in UART communication line is detected based on communication error

Radio and display receiver assembly

CAUTION / NOTICE / HINT

NOTICE:

  • Depending on the parts that are replaced during vehicle inspection or maintenance, performing initialization, registration or calibration may be needed. Refer to Precaution for Navigation System.

    Click here

  • When replacing the radio and display receiver assembly, always replace it with a new one. If a radio and display receiver assembly which was installed to another vehicle is used, the following may occur:
    • A communication malfunction DTC may be stored.
    • The radio and display receiver assembly may not operate normally.

PROCEDURE

1.

CHECK DTC

(a) Clear the DTCs.

Body Electrical > Navigation System > Clear DTCs

(b) Recheck for DTCs and check that no DTCs are output.

Body Electrical > Navigation System > Trouble Codes

OK:

No DTCs are output.

OK

USE SIMULATION METHOD TO CHECK

NG

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY

Extension Module Malfunction 2 (B1556)

DESCRIPTION

These DTCs are stored when a malfunction occurs in the Navigation ECU.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B1556

Extension Module Malfunction 2

When any of the following conditions is met:

  • Internal power supply malfunction
  • Internal hard drive malfunction
  • EEPROM error
  • Storage malfunction

Navigation ECU

CAUTION / NOTICE / HINT

NOTICE:

When replacing the navigation ECU, always replace it with a new one. If a navigation ECU which was installed to another vehicle is used, the following may occur:

  • A communication malfunction DTC may be stored.
  • The navigation ECU may not operate normally.

PROCEDURE

1.

CHECK DTC

(a) Clear the DTCs.

Body Electrical > Navigation System > Clear DTCs

(b) Recheck for DTCs and check that no DTCs are output.

Body Electrical > Navigation System > Trouble Codes

OK:

No DTCs are output.

OK

USE SIMULATION METHOD TO CHECK

NG

REPLACE NAVIGATION ECU

Lost Communication with Meter (B1324,B1325)

Voice Recognition Microphone Disconnected (B1579). USB Device Malfunction (B1585). Black Screen

See More:

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual > Electronically Controlled Brake System(for Gasoline Model): TRAC does not Operate. Vehicle Control History. VSC does not Operate or VSC does not Operate Correctly
TRAC does not Operate DESCRIPTION When TRAC or VSC is operating, the skid control ECU (brake actuator assembly) blinks the slip indicator light to inform the driver that slippage occurred. When in VSC off mode, or TRAC and VSC are disabled, the multi-information display in the combination meter asse ...

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual

© 2025 Copyright audio-visual-telematics.tavalon.net
0.1484