Toyota Avalon Service & Repair Manual: UART Communication Between ANC and Audio Amplifier Missing Message (B1AA187)

Toyota Avalon Service & Repair Manual / Audio, Visual, Telematics / Audio / Video / Active Noise Control System / UART Communication Between ANC and Audio Amplifier Missing Message (B1AA187)

DESCRIPTION

This DTC is stored when an UART communication error occurs between the stereo component equalizer assembly and stereo component amplifier assembly.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
B1AA187	UART Communication Between ANC and Audio Amplifier Missing Message	Stereo component equalizer assembly detects a UART communication malfunction in stereo component amplifier assembly for 4 seconds or more continuously*	Harness or connector Stereo component amplifier assembly Stereo component equalizer assembly

HINT:

*: Malfunction monitoring is not performed under the following conditions, in order to prevent erroneous detection.

After engine switch is turned on (ACC) for 3 seconds or more.
After the battery voltage returns to normal for 3 seconds.
Before 3 seconds have elapsed after battery voltage has returned to normal.

WIRING DIAGRAM

PROCEDURE

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Active Noise Control > Clear DTCs

2.	CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Active Noise Control > Trouble Codes

OK:

DTC B1AA187 is not output.

USE SIMULATION METHOD TO CHECK

3.	CHECK HARNESS AND CONNECTOR (STEREO COMPONENT EQUALIZER ASSEMBLY - STEREO COMPONENT AMPLIFIER ASSEMBLY)

(a) Disconnect the G68 stereo component equalizer assembly connector.

(b) Disconnect the G69 stereo component amplifier assembly connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
G68-2 (ACK1) - G69-2 (ACK1)	Always	Below 1 Ω
G68-16 (ACK2) - G69-10 (ACK2)	Always	Below 1 Ω
G68-2 (ACK1) or G69-2 (ACK1) - Body ground	Always	10 kΩ or higher
G68-16 (ACK2) or G69-10 (ACK2) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	REPLACE STEREO COMPONENT EQUALIZER ASSEMBLY

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

Click here

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Active Noise Control > Clear DTCs

6.	CHECK FOR DTC

(a) Check for DTCs.

Body Electrical > Active Noise Control > Trouble Codes

OK:

DTC B1AA187 is not output.

END (STEREO COMPONENT AMPLIFIER ASSEMBLY IS DEFECTIVE)

REPLACE STEREO COMPONENT EQUALIZER ASSEMBLY

ANC ECU EEPROM Data Memory Failure (B1AA044)

Front Left Microphone Circuit Component Internal Failure (B1AA296,B1AA31C)

See More:

Toyota Avalon Owners Manual > Driving procedures: Automatic transmission
Shifting the shift lever While the engine switch is in IGNITION ON mode and the brake pedal depressed*, shift the shift lever while pushing the shift release button on the shift knob. Shift the shift lever while pushing the shift release button on the shift knob. Shift the shift lever normally. When ...