DTC B1543: Extension Module Disconnected 2 [06/2017 - ]: Procedure

1. Turn the engine switch on (ACC) and wait for 90 seconds.
2. Press the "MAP" switch and check that the map screen is displayed normally.

   Result

   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)

Result: 

A 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2017 - 08/2018]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2018 - 09/2019]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2019 - 03/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2020 - 10/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2020 - 08/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2021 - ] 

Result: 

B 

See step  2

1. Clear the DTCs.

   Body Electrical > Navigation System > Clear DTCs 

2. Turn the engine switch off.
3. Turn the engine switch on (IG) and wait for 90 seconds.
4. Recheck for DTCs and check that no DTCs are output.

   Body Electrical > Navigation System > Trouble Codes 

   OK

   No DTCs are output.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2017 - 08/2018]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2018 - 09/2019]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2019 - 03/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2020 - 10/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2020 - 08/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2021 - ] 

Result: 

NG 

See step  3

1. Disconnect the navigation ECU connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   K17-23 (GND) - Body ground	Always	Below 1 Ω

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   K17-10 (+B) - Body ground	Always	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

1. Disconnect the r1 navigation ECU connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

2. Disconnect the r3 radio and display receiver assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   r1-4 (US4+) - r3-1 (US4+)	Always	Below 1 Ω
   r1-5 (US4-) - r3-2 (US4-)	Always	Below 1 Ω
   r1-6 (UGD4) - r3-3 (UGD4)	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE NO. 1 NAVIGATION WIRE. Refer to  REMOVAL [06/2017 - 10/2020]  , or refer to  REMOVAL [10/2020 - ] 

Result: 

OK 

See step  5

1. Replace the navigation ECU with a new one.

   Refer to REMOVAL [06/2017 - 10/2020] , or refer to REMOVAL [10/2020 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  6

1. Clear the DTCs.

   Body Electrical > Navigation System > Clear DTCs 

2. Turn the engine switch off.
3. Turn the engine switch on (IG) and wait for 90 seconds.
4. Recheck for DTCs and check that no DTCs are output.

   Body Electrical > Navigation System > Trouble Codes 

   OK

   No DTCs are output.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

END (NAVIGATION ECU IS DEFECTIVE) 

Result: 

NG 

REPLACE RADIO AND DISPLAY RECEIVER ASSEMBLY. Refer to  REMOVAL [06/2017 - 10/2020]  , or refer to  REMOVAL [10/2020 - ]