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 audio and visual 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 audio and visual system will not operate normally.
DTC No. | Detection Item | DTC Detection Condition | Trouble Area |
---|---|---|---|
B1543 | Extension Module Disconnected 2 | Navigation ECU disconnected |
|
HINT:
This DTC may be stored due to environmental reasons such as electrical noise or interference.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
Click here
PROCEDURE
1. | CHECK COMPASS SCREEN |
(a) Turn the engine switch on (ACC) and wait for 60 seconds.
(b) Press the "MAP" switch and check that the compass screen is displayed normally.
Result | Proceed to |
---|---|
Compass screen is displayed normally | A |
Compass screen is not displayed normally | B |
HINT:
A | ![]() | USE SIMULATION METHOD TO CHECK |
|
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 CodesOK:
No DTCs are output.
OK | ![]() | USE SIMULATION METHOD TO CHECK |
|
3. | CHECK HARNESS AND CONNECTOR (NAVIGATION ECU POWER SOURCE) |
(a) Disconnect the J153 navigation ECU connector. |
|
(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 |
|
4. | CHECK NO. 1 NAVIGATION WIRE (RADIO RECEIVER ASSEMBLY - NAVIGATION ECU) |
(a) Disconnect the z31 radio receiver assembly connector. |
|
(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 |
|
5. | REPLACE NAVIGATION ECU |
(a) Replace the navigation ECU with a new or known good one.
Click here
|
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 CodesOK:
No DTCs are output.
OK | ![]() | END (NAVIGATION ECU IS DEFECTIVE) |
NG | ![]() | REPLACE RADIO RECEIVER ASSEMBLY |
Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Blind Spot Monitor System: Vehicle Speed Sensor (C1A45)
DESCRIPTION The blind spot monitor sensor receives vehicle speed signals from the skid control ECU via CAN communication. DTC No. Detection Item DTC Detection Condition Trouble Area C1A45 Vehicle Speed Sensor A fail flag is transmitted from the skid control ECU
Vehicle stabilit ...
Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Navigation System: Radio Broadcast cannot be Received or Poor Reception
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 PROCEDURE 1. CHECK RADIO RECEIVER ASSEMBLY (a) Che ...