DTC B1543: Extension Module Disconnected 2 [06/2018 - 09/2022]: Procedure

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2022 Lexus ES 350, 2022 Lexus ES 250, 2021 Lexus ES 350, 2021 Lexus ES 250, and 2020 Lexus ES 350. However, it is still accessible from the selected car via links, so may be relevant.

CHECK COMPASS SCREEN

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

Press the "MAP" switch and check that the compass screen is displayed normally.

Result

Result	Proceed to
Compass screen is displayed normally	A
Compass 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 compass screen is displayed normally. (Codes stored due to past environmental factors)

Result:

USE SIMULATION METHOD TO CHECK. Refer to HOW TO PROCEED WITH TROUBLESHOOTING [06/2018 - ]

Result:

See step 2

CHECK DTC

Clear the DTCs.
Body Electrical > Navigation System > Clear DTCs
Turn the engine switch off.
Turn the engine switch on (IG) and wait for 90 seconds.

Recheck for DTCs and check that no DTCs are output.

Body Electrical > Navigation System > Trouble Codes

No DTCs are output.

Result

Proceed to
OK
NG

Result:

USE SIMULATION METHOD TO CHECK. Refer to HOW TO PROCEED WITH TROUBLESHOOTING [06/2018 - ]

Result:

See step 3

CHECK HARNESS AND CONNECTOR (NAVIGATION ECU POWER SOURCE)

Disconnect the G14 navigation ECU connector.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*a	Front view of wire harness connector (to Navigation ECU)

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

Standard Resistance

Tester Connection	Condition	Specified Condition
G14-23 (GND) - Body ground	Always	Below 1 Ω

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

Standard Voltage

Tester Connection	Condition	Specified Condition
G14-10 (+B) - Body ground	Always	11 to 14 V

Result

Proceed to
OK
NG

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 4

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

Disconnect the I1 radio receiver assembly connector.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*a	Front view of wire harness connector (to Navigation ECU)
*b	Front view of wire harness connector (to Radio Receiver Assembly)

Disconnect the I2 navigation ECU connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
I1-4 (USB+) - I2-4 (USB+)	Always	Below 1 Ω
I1-5 (USB-) - I2-5 (USB-)	Always	Below 1 Ω
I1-6 (USBS) - I2-6 (USBS)	Always	Below 1 Ω

Result

Proceed to
OK
NG

Result:

REPLACE NO. 1 NAVIGATION WIRE. Refer to REMOVAL [06/2018 - 08/2020] , or refer to REMOVAL [08/2020 - 09/2022]

Result:

See step 5

REPLACE NAVIGATION ECU

Replace the navigation ECU with a new one.

Refer to REMOVAL [06/2018 - 08/2020] , or refer to REMOVAL [08/2020 - 09/2022]

Result

Proceed to
NEXT

Result:

See step 6

CHECK DTC

Clear the DTCs.
Body Electrical > Navigation System > Clear DTCs
Turn the engine switch off.
Turn the engine switch on (IG) and wait for 90 seconds.

Recheck for DTCs and check that no DTCs are output.

Body Electrical > Navigation System > Trouble Codes

No DTCs are output.

Result

Proceed to
OK
NG

Result:

END (NAVIGATION ECU IS DEFECTIVE)

Result:

REPLACE RADIO RECEIVER ASSEMBLY. Refer to REMOVAL [06/2018 - 08/2020] , or refer to REMOVAL [08/2020 - 09/2022]