DTC B1549-13: Voice Recognition Microphone2 Circuit Open [09/2022 - ]: Procedure

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2024 Lexus ES 350, 2024 Lexus ES 300h, 2024 Lexus ES 250, 2023 Lexus ES 350, and 2023 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.

CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - TELEPHONE MICROPHONE ASSEMBLY RH)

Disconnect the G144 radio receiver assembly connector.
Disconnect the P23 telephone microphone assembly RH connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
G144-21 (SNS2) - P23-5 (SNS2)	Always	Below 1 Ω
G144-18 (MI2-) - P23-4 (MO2-)	Always	Below 1 Ω
G144-21 (SNS2) or P23-5 (SNS2) - Body ground	Always	10 kΩ or higher
G144-18 (MI2-) or P23-4 (MO2-) - Body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 2

INSPECT RADIO RECEIVER ASSEMBLY (MI2-)

With the radio receiver assembly connectors connected, disconnect the P23 telephone microphone assembly RH connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
P23-4 (MO2-) - Body ground	Always	Below 1 Ω

Result

Proceed to
OK
NG

Result:

REPLACE RADIO RECEIVER ASSEMBLY. Refer to REMOVAL [09/2022 - ]

Result:

See step 3

INSPECT TELEPHONE MICROPHONE ASSEMBLY RH (SNS2, MO2-)

Remove the telephone microphone assembly RH.

*a	Component without harness connected (Telephone microphone assembly RH)

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

Standard Resistance

Tester Connection	Condition	Specified Condition
5 (SNS2) - 4 (MO2-)	Always	Below 1 Ω

Result

Proceed to
OK
NG

Result:

REPLACE RADIO RECEIVER ASSEMBLY. Refer to REMOVAL [09/2022 - ]

Result:

REPLACE TELEPHONE MICROPHONE ASSEMBLY RH. Refer to REMOVAL [09/2022 - ]