DTC B156C: Extension Module Disconnected [12/2015 - 11/2017]: Procedure

1. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [12/2015 - 11/2017]

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

   Refer to DTC CHECK / CLEAR [12/2015 - 11/2017]

   OK

   No DTCs are output.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2015 - 08/2016]  Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2016 - 11/2017] 

Result: 

NG 

See step  2

1. Disconnect the Z1 navigation receiver assembly connectors.
2. Disconnect the Z2 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
   Z1-4 (+B2) - Z2-4 (+B2)	Always	Below 1 Ω
   Z1-3 (ACC2) - Z2-3 (ACC2)	Always	Below 1 Ω
   Z1-8 (GND2) - Z2-8 (GND2)	Always	Below 1 Ω
   Z1-4 (+B2) - Body ground	Always	10 kΩ or higher
   Z1-3 (ACC2) - Body ground	Always	10 kΩ or higher
   Z1-8 (GND2) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Disconnect the 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
   Z2-4 (+B2) - Z2-8 (GND2)	Always	11 to 14 V
   Z2-3 (ACC2) - Z2-8 (GND2)	Ignition switch ACC	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE NAVIGATION RECEIVER ASSEMBLY. Refer to  REMOVAL [12/2015 - 11/2017] 

Result: 

OK 

See step  4

1. Disconnect the V3 navigation receiver assembly connectors.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

2. Disconnect the V4 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
   V3-1 (USV4) - V4-1 (USV4)	Always	Below 1 Ω
   V3-2 (US4-) - V4-2 (US4-)	Always	Below 1 Ω
   V3-3 (US4+) - V4-3 (US4+)	Always	Below 1 Ω
   V3-4 (UGD4) - V4-4 (UGD4)	Always	Below 1 Ω
   V3-5 (USG4) - V4-5 (USG4)	Always	Below 1 Ω
   V3-1 (USV4) - Body ground	Always	10 kΩ or higher
   V3-2 (US4-) - Body ground	Always	10 kΩ or higher
   V3-3 (US4+) - Body ground	Always	10 kΩ or higher
   V3-4 (UGD4) - Body ground	Always	10 kΩ or higher
   V3-5 (USG4) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

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

   Refer to REMOVAL [12/2015 - 11/2017]

2. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [12/2015 - 11/2017]

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

   Refer to DTC CHECK / CLEAR [12/2015 - 11/2017]

   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 [12/2015 - 11/2017]