DTC B15D0: MOST Communication Malfunction [10/2014 - 09/2017]: Procedure

1. Check that optional components (including associated wiring) which generate radio waves are not installed.

   Result

   Result	Proceed to
   Optional components (including associated wiring) are installed.	A
   Optional components (including associated wiring) are not installed.	B

   HINT: 

   • Electrical noise from radio waves generated by optional components or the wiring for those components may affect AVC-LAN communication.
   • These DTCs may be stored when an AVC-LAN communication error occurs due to electrical noise.

Result: 

B 

See step  3

Result: 

A 

See step  2

1. Turn the engine switch off.
2. Turn the engine switch on (ACC) and check if the audio system activates and if the speakers operate.

   HINT: 

   • Choose a source such as radio so that sound can be output from the speakers.
   • If sound from the speakers is low, turn up the volume.

   Result

   Result	Proceed to
   Even after the engine switch is turned on (ACC), the navigation system does not activate and sound is not output from the speakers.	A
   The audio system activates when the engine switch is turned on (ACC) but the sound stops being output when the amplifier output exceeds a certain level.	B

   HINT: 

   • If a short occurs in a speaker circuit, the sound from the corresponding speaker will be low or almost impossible to hear. If the volume is turned up in this situation, to prevent excessive current flow due to the short circuit, the stereo component amplifier assembly stops operating when its output exceeds a certain level. When the operation of the stereo component amplifier assembly stops, the navigation system will not function normally. This is because MOST communication will stop due to the shut down of the amplifier causing an error in the MOST network. The stereo component amplifier assembly will start operating again when the engine switch is turned off and back on (ACC) again. However, the amplifier will stop operating again if its output exceeds a certain level.
   • When the stereo component amplifier assembly stops operating and a malfunction occurs in the navigation system due to a short in a speaker circuit, this DTC will be stored. In this case, check each speaker circuit and repair or replace malfunctioning parts, and then recheck for DTCs.

Result: 

B 

GO TO AUDIO AND VISUAL SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2014 - 09/2017] 

Result: 

A 

See step  3

1. Display the "MOST Line Check" screen.

   Refer to DTC CHECK / CLEAR [10/2014 - 09/2017]

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Node position number for devices that use MOST communication
   *b	Device name
   *c	Result

2. Check the result on the "MOST Line Check" screen.

   Result

   Result	Proceed to
   "NCON" is displayed for "AMP".	A
   "OK" is displayed for all items.	B

   • When "NCON" is displayed for more than 1 item, proceed to the step for the device that has the smallest node position number.
   • The "MOST Line Check" screen can be displayed only when DTC B15D0 is stored.

Result: 

B 

See step  7

Result: 

A 

See step  4

1. Check the MOST communication line connectors.
   1. Check if the MOST communication line connector between the radio receiver assembly and stereo component amplifier assembly has any connection problems.

      Refer to DTC CHECK / CLEAR [10/2014 - 09/2017]

2. Display the "MOST Line Check" screen and check the result.

   Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [10/2014 - ]

   Result

   Result	Proceed to
   "NCON" is displayed for "AMP".	A
   The screen cannot be changed to the "MOST Line Check" screen.	B

   HINT: 

   When the malfunction in the MOST network is repaired, the screen cannot be changed to the "MOST Line Check" screen.

Result: 

B 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2014 - 09/2017] 

Result: 

A 

See step  5

1. Disconnect the stereo component amplifier assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   P29-8 (WUI) - Body ground	Engine switch on (ACC)	4.5 V or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to  REMOVAL [10/2014 - 09/2017] 

Result: 

NG 

See step  6

1. Disconnect the I102 radio receiver assembly connector.
2. Disconnect the P29 stereo component amplifier assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   I102-1 (WUO) - P29-8 (WUI)	Always	Below 1 Ω
   I102-1 (WUO) or P29-8 (WUI) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  7

1. Disconnect the I102 radio receiver assembly connector.
2. Disconnect the P29 stereo component amplifier assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   I102-2 (MI+) - P29-5 (MO+)	Always	Below 1 Ω
   I102-3 (MI-) - P29-6 (MO-)	Always	Below 1 Ω
   I102-4 (SLDI) - P29-7 (SLDO)	Always	Below 1 Ω
   I102-5 (MO+) - P29-2 (MI+)	Always	Below 1 Ω
   I102-6 (MO-) - P29-3 (MI-)	Always	Below 1 Ω
   I102-7 (SLDO) - P29-4 (SLDI)	Always	Below 1 Ω
   I102-2 (MI+) or P29-5 (MO+) - Body ground	Always	10 kΩ or higher
   I102-3 (MI-) or P29-6 (MO-) - Body ground	Always	10 kΩ or higher
   I102-4 (SLDI) or P29-7 (SLDO) - Body ground	Always	10 kΩ or higher
   I102-5 (MO+) or P29-2 (MI+) - Body ground	Always	10 kΩ or higher
   I102-6 (MO-) or P29-3 (MI-) - Body ground	Always	10 kΩ or higher
   I102-7 (SLDO) or P29-4 (SLDI) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  8

1. Replace the stereo component amplifier assembly.

   Refer to REMOVAL [10/2014 - 09/2017]

2. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [10/2014 - 09/2017]

   Body Electrical > Navigation System > Clear DTCs 

3. Recheck for DTCs and check that no DTCs are output.

   Refer to DTC CHECK / CLEAR [10/2014 - 09/2017]

   Body Electrical > Navigation System > Trouble Codes 

   OK

   No DTCs are output.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

END (STEREO COMPONENT AMPLIFIER ASSEMBLY IS DEFECTIVE) 

Result: 

NG 

REPLACE RADIO RECEIVER ASSEMBLY. Refer to  REMOVAL [10/2014 - 09/2017]