DTC B1AA1-87: UART Communication Between ANC and Audio Amplifier Missing Message [02/2024 - ]: Procedure

1. Clear the DTCs.

   Body Electrical > Active Noise Control > Clear DTCs 

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  2

1. Check for DTCs.

   Body Electrical > Active Noise Control > Trouble Codes 

   Result

   Result	Proceed to
   B1AA1-87 is not output	A
   B1AA1-87 is output	B

Result: 

A 

USE SIMULATION METHOD TO CHECK 

Refer to HOW TO PROCEED WITH TROUBLESHOOTING [02/2024 - ]

Result: 

B 

See step  3

Pre-procedure1

1. Disconnect the L7 stereo component amplifier assembly connector.
2. Disconnect the L15 stereo component equalizer assembly connector.

   Procedure1

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   L7-2 (ACK1) - L15-2 (ACK1)	Always	Below 1 Ω
   L7-10 (ACK2) - L15-16 (ACK2)	Always	Below 1 Ω
   L7-2 (ACK1) - Body ground	Always	10 kΩ or higher
   L7-10 (ACK2) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

   Post-procedure1

4. None

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.

   HINT: 

   Refer to REMOVAL [02/2024 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  5

1. Clear the DTCs.

   Body Electrical > Active Noise Control > Clear DTCs 

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  6

1. Check for DTCs.

   Body Electrical > Active Noise Control > Trouble Codes 

   Result

   Result	Proceed to
   B1AA1-87 is not output	A
   B1AA1-87 is output	B

Result: 

A 

END (STEREO COMPONENT AMPLIFIER ASSEMBLY IS DEFECTIVE) 

Result: 

B 

REPLACE STEREO COMPONENT EQUALIZER ASSEMBLY 

Refer to REMOVAL [02/2024 - ]