DTC B15D0: MOST Communication Malfunction [12/2019 - 10/2022]: Procedure

1. Check for DTCs.

   Body Electrical > Navigation System > Trouble Codes 

   Result

   Result	Proceed to
   DTC B15C3 and B15D3 are not output	A
   DTC B15C3 is output	B
   DTC B15D3 is output	C

   HINT: 

   • If a short occurs in a speaker circuit, the sound output from the speakers will become very low or will stop and DTC B15C3 will be stored.

     In this case, if the audio system volume is increased, current in the speaker circuit will increase more than necessary.

     To prevent the current from becoming excessively high, when it increases to a certain amount, operation of the stereo component amplifier assembly will be suspended.

     If operation is suspended, MOST communication will become impossible, the navigation system will not operate normally and DTC B15D0 will be stored.

   • If DTC B15C3 and B15D3 are output at the same time, perform troubleshooting for DTC B15C3 first.

Result: 

B 

GO TO DTC B15C3. Refer to  DTC B15C3: Speaker Output Short [12/2019 - 10/2022]  

Result: 

C 

GO TO B15D3. Refer to  DTC B15D3: Stereo Component Amplifier Disconnected [12/2019 - 10/2022]  

Result: 

A 

See step  2

1. Enter the "MOST Line Check" screen. Refer to Check DTC (Check Using System Check Mode Screen) in DTC Check / Clear.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	MOST Network Device Node Position Number
   *b	Device Name
   *c	Result

   Refer to DTC CHECK / CLEAR [12/2019 - 10/2022]

   HINT: 

   "MOST" is displayed on "System Check Mode" screen when the MOST network is malfunctioning.

   Result

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

Result: 

B 

See step  5

Result: 

A 

See step  3

1. Disconnect the H102 radio receiver assembly connector.
2. Disconnect the M99 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
   H102-2 (MI+) - M99-5 (MO+)	Always	Below 1 Ω
   H102-3 (MI-) - M99-6 (MO-)	Always	Below 1 Ω
   H102-4 (SLDI) - M99-7 (SLDO)	Always	Below 1 Ω
   H102-5 (MO+) - M99-2 (MI+)	Always	Below 1 Ω
   H102-6 (MO-) - M99-3 (MI-)	Always	Below 1 Ω
   H102-7 (SLDO) - M99-4 (SLDI)	Always	Below 1 Ω
   H102-2 (MI+) or M99-5 (MO+) - Body ground	Always	10 kΩ or higher
   H102-3 (MI-) or M99-6 (MO-) - Body ground	Always	10 kΩ or higher
   H102-4 (SLDI) or M99-7 (SLDO) - Body ground	Always	10 kΩ or higher
   H102-5 (MO+) or M99-2 (MI+) - Body ground	Always	10 kΩ or higher
   H102-6 (MO-) or M99-3 (MI-) - Body ground	Always	10 kΩ or higher
   H102-7 (SLDO) or M99-4 (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  4

1. Replace the stereo component amplifier assembly with a new or known good one.

   Refer to REMOVAL [12/2019 - ]

2. Clear the DTCs.

   Body Electrical > Navigation System > Clear DTCs 

3. 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 

Result: 

NG 

REPLACE RADIO RECEIVER ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022] 

1. Disconnect the M99 stereo component amplifier assembly connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   M99-8 (WUI) - Body ground	Ignition switch ACC	4.5 V or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to  REMOVAL [12/2019 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR