DTC B156C: Extension Module Disconnected [09/2016 - ]: Procedure

1. Clear the DTCs.

   Body Electrical > Navigation System > Clear DTCs 

2. Turn the power switch off.
3. Check for DTCs.

   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 [09/2016 - 05/2019]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [05/2019 - 07/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [07/2020 - 06/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2021 - ] 

Result: 

NG 

See step  2

1. Disconnect the o1 navigation receiver assembly connector.
2. Disconnect the o2 stereo component tuner assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   o1-4 (+B2) - o2-4 (+B2)	Always	Below 1 Ω
   o1-3 (ACC2) - o2-3 (ACC2)	Always	Below 1 Ω
   o1-8 (GND2) - o2-8 (GND2)	Always	Below 1 Ω
   o1-4 (+B2) - Body ground	Always	10 kΩ or higher
   o1-3 (ACC2) - Body ground	Always	10 kΩ or higher
   o1-8 (GND2) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE NO. 1 NAVIGATION WIRE. Refer to  REMOVAL [09/2016 - 05/2019]  , or refer to  REMOVAL [05/2019 - 07/2020]  , or refer to  REMOVAL [07/2020 - ] 

Result: 

OK 

See step  3

1. Disconnect the o2 stereo component tuner assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Stereo Component Tuner Assembly)

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   o2-4 (+B2) - o2-8 (GND2)	Power switch off	11 to 14 V
   o2-3 (ACC2) - o2-8 (GND2)	Power switch on (ACC)	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE NAVIGATION RECEIVER ASSEMBLY. Refer to  REMOVAL [09/2016 - 05/2019]  , or refer to  REMOVAL [05/2019 - 07/2020]  , or refer to  REMOVAL [07/2020 - ] 

Result: 

OK 

See step  4

1. Disconnect the o3 navigation receiver assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Navigation Receiver Assembly)
   *b	Front view of wire harness connector (to Stereo Component Tuner Assembly)

2. Disconnect the o4 stereo component tuner assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   o3-1 (USV4) - o4-1 (USV4)	Always	Below 1 Ω
   o3-2 (US4-) - o4-2 (US4-)	Always	Below 1 Ω
   o3-3 (US4+) - o4-3 (US4+)	Always	Below 1 Ω
   o3-4 (UGD4) - o4-4 (UGD4)	Always	Below 1 Ω
   o3-5 (USG4) - o4-5 (USG4)	Always	Below 1 Ω
   o3-1 (USV4) - Body ground	Always	10 kΩ or higher
   o3-2 (US4-) - Body ground	Always	10 kΩ or higher
   o3-3 (US4+) - Body ground	Always	10 kΩ or higher
   o3-4 (UGD4) - Body ground	Always	10 kΩ or higher
   o3-5 (USG4) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE NO. 1 NAVIGATION WIRE. Refer to  REMOVAL [09/2016 - 05/2019]  , or refer to  REMOVAL [05/2019 - 07/2020]  , or refer to  REMOVAL [07/2020 - ] 

Result: 

OK 

See step  5

1. Replace the stereo component tuner assembly with a known good one.

   Refer to REMOVAL [09/2016 - 05/2019] , or refer to REMOVAL [05/2019 - 07/2020] , or refer to REMOVAL [07/2020 - ]

2. Clear the DTCs.

   Body Electrical > Navigation System > Clear DTCs 

3. Turn the power switch off.
4. Check for DTCs.

   Body Electrical > Navigation System > Trouble Codes 

   OK

   No DTCs are output.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

END (STEREO COMPONENT TUNER ASSEMBLY IS DEFECTIVE) 

Result: 

NG 

REPLACE NAVIGATION RECEIVER ASSEMBLY. Refer to  REMOVAL [09/2016 - 05/2019]  , or refer to  REMOVAL [05/2019 - 07/2020]  , or refer to  REMOVAL [07/2020 - ]