Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Extension Module Disconnected 2 (B1543)

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Audio & Visual & Telematics / Navigation / Multi Info Display / Navigation System / Extension Module Disconnected 2 (B1543)

DESCRIPTION

If the radio 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 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 receiver assembly
  • No. 1 navigation wire
  • 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 fuse for circuits related to this system before performing the following procedure.

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 POWER SOURCE)

(a) Disconnect the J153 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

J153-23 (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

J153-10 (+B) - Body ground

Always

11 to 14 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

CHECK NO. 1 NAVIGATION WIRE (RADIO RECEIVER ASSEMBLY - NAVIGATION ECU)

(a) Disconnect the z31 radio receiver assembly connector.

*a

Front view of wire harness connector

(to Navigation ECU)

*b

Front view of wire harness connector

(to Radio Receiver Assembly)

(b) Disconnect the z32 navigation ECU connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

z31-4 (US4+) - z32-4 (US4+)

Always

Below 1 Ω

z31-5 (US4-) - z32-5 (US4-)

Always

Below 1 Ω

z31-6 (UGD4) - z32-6 (UGD4)

Always

Below 1 Ω
NG

REPLACE NO. 1 NAVIGATION WIRE

OK

5.

REPLACE NAVIGATION ECU

(a) Replace the navigation ECU with a new or known good 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 RECEIVER ASSEMBLY

    Operation Check
    OPERATION CHECK CHECK NAVIGATION SYSTEM NORMAL CONDITION (a) If the cause of a symptom is any of the following, the corresponding symptom is normal; it is not due to a malfunction. Symptom Answer ...

    HD Radio Tuner Malfunction (B1551,B15A0,B15B3-B15B5,B15B7,B15BA,B15F9)
    DESCRIPTION These DTCs are stored when a malfunction occurs in the radio receiver assembly DTC No. Detection Item DTC Detection Condition Trouble Area B1551 HD Radio Tuner Malfunction ...

    Other materials:

    Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Towing Converter Relay: Components
    COMPONENTS ILLUSTRATION *1 DECK BOARD ASSEMBLY *2 DECK SIDE TRIM BOX RH *3 REAR DECK FLOOR BOX *4 REAR FLOOR FINISH PLATE *5 REAR NO. 3 FLOOR BOARD *6 REAR NO. 4 FLOOR BOARD *7 TONNEAU COVER ASSEMBLY - - ILLUSTRATION *A w/o Rear Power Seat System *B ...

    Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Telephone And Gps Antenna (for Roof Side): Removal
    REMOVAL CAUTION / NOTICE / HINT The necessary procedures (adjustment, calibration, initialization, or registration) that must be performed after parts are removed and installed, or replaced during telephone and GPS antenna assembly removal/installation are shown below. Necessary Procedures After Par ...

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual

    © 2025 Copyright www.lexusrx.net
    0.0199