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

CHECK FOR DTC

Clear the DTCs.
Body Electrical > Navigation System > Clear DTCs
Turn the power switch off.

Check for DTCs.

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 [11/2015 - 12/2018] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2018 - 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:

See step 2

CHECK NO. 1 NAVIGATION WIRE (NAVIGATION RECEIVER ASSEMBLY - STEREO COMPONENT TUNER ASSEMBLY)

Disconnect the p1 navigation receiver assembly connector.
Disconnect the p2 stereo component tuner assembly connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
p1-4 (+B2) - p2-4 (+B2)	Always	Below 1 Ω
p1-3 (ACC2) - p2-3 (ACC2)	Always	Below 1 Ω
p1-8 (GND2) - p2-8 (GND2)	Always	Below 1 Ω
p1-4 (+B2) - Body ground	Always	10 kΩ or higher
p1-3 (ACC2) - Body ground	Always	10 kΩ or higher
p1-8 (GND2) - Body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

Result:

REPLACE NO. 1 NAVIGATION WIRE. Refer to REMOVAL [11/2015 - 11/2017] , or refer to REMOVAL [11/2017 - 12/2018] , or refer to REMOVAL [12/2018 - 08/2019] , or refer to REMOVAL [08/2019 - 07/2020] , or refer to REMOVAL [07/2020 - ]

Result:

See step 3

INSPECT NAVIGATION RECEIVER ASSEMBLY

Disconnect the p2 stereo component tuner assembly connector.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

Standard Voltage

Tester Connection	Condition	Specified Condition
p2-4 (+B2) - p2-8 (GND2)	Power switch off	11 to 14 V
p2-3 (ACC2) - p2-8 (GND2)	Power switch on (ACC)	11 to 14 V

Result

Proceed to
OK
NG

Result:

REPLACE NAVIGATION RECEIVER ASSEMBLY. Refer to REMOVAL [11/2015 - 11/2017] , or refer to REMOVAL [11/2017 - 12/2018] , or refer to REMOVAL [12/2018 - 08/2019] , or refer to REMOVAL [08/2019 - 07/2020] , or refer to REMOVAL [07/2020 - ]

Result:

See step 4

CHECK NO. 1 NAVIGATION WIRE (USB COMMUNICATION LINE)

Disconnect the p3 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)

Disconnect the p4 stereo component tuner assembly connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
p3-1 (USV4) - p4-1 (USV4)	Always	Below 1 Ω
p3-2 (US4-) - p4-2 (US4-)	Always	Below 1 Ω
p3-3 (US4+) - p4-3 (US4+)	Always	Below 1 Ω
p3-4 (UGD4) - p4-4 (UGD4)	Always	Below 1 Ω
p3-5 (USG4) - p4-5 (USG4)	Always	Below 1 Ω
p3-1 (USV4) - Body ground	Always	10 kΩ or higher
p3-2 (US4-) - Body ground	Always	10 kΩ or higher
p3-3 (US4+) - Body ground	Always	10 kΩ or higher
p3-4 (UGD4) - Body ground	Always	10 kΩ or higher
p3-5 (USG4) - Body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

Result:

See step 5

CHECK STEREO COMPONENT TUNER ASSEMBLY

Replace the stereo component tuner assembly with a known good one.
Refer to REMOVAL [11/2015 - 11/2017] , or refer to REMOVAL [11/2017 - 12/2018] , or refer to REMOVAL [12/2018 - 08/2019] , or refer to REMOVAL [08/2019 - 07/2020] , or refer to REMOVAL [07/2020 - ]
Clear the DTCs.
Body Electrical > Navigation System > Clear DTCs
Turn the power switch off.

Check for DTCs.

Body Electrical > Navigation System > Trouble Codes

No DTCs are output.

Result

Proceed to
OK
NG

Result:

END (STEREO COMPONENT TUNER ASSEMBLY IS DEFECTIVE)

Result: