Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Microphone Circuit Open (B157213)

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Audio & Visual & Telematics / Cellular Communication / Safety Connect System / Microphone Circuit Open (B157213)

DESCRIPTION

This DTC is stored when the DCM (telematics transceiver) detects a malfunction in the telephone microphone assembly circuit.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B157213

Microphone Circuit Open

Current at terminal MCVD is lower than the malfunction threshold for 10 seconds or more while the engine switch is on (IG)
  • DCM (telematics transceiver)
  • Telephone microphone assembly
  • Harness or connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Depending on the parts that are replaced during vehicle inspection or maintenance, performing initialization, registration or calibration may be needed. Refer to Precaution for Safety Connect System.

Click here

PROCEDURE

1.

CHECK DTC

(a) Turn the engine switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the engine switch on (IG) and wait for 10 seconds or more.

(d) Turn the Techstream on.

(e) Clear the DTCs.

Body Electrical > Telematics > Clear DTCs

(f) Check for DTCs and check that no DTCs are output.

Body Electrical > Telematics > Trouble Codes

OK:

No DTCs are output.

OK

USE SIMULATION METHOD TO CHECK

NG

2.

CHECK HARNESS AND CONNECTOR (DCM [TELEMATICS TRANSCEIVER] - TELEPHONE MICROPHONE ASSEMBLY)

(a) Disconnect the J157 DCM (telematics transceiver) connector.

(b) Disconnect the U15 telephone microphone assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J157-5 (MCVD) - U15-1 (MACC)

Always

Below 1 Ω

J157-6 (MCI+) - U15-2 (MIC+)

Always

Below 1 Ω

J157-7 (MCI-) - U15-4 (MIC-)

Always

Below 1 Ω

J157-23 (SGND) - Body ground

Always

10 kΩ or higher

J157-5 (MCVD) or U15-1 (MACC) - Body ground

Always

10 kΩ or higher

J157-6 (MCI+) or U15-2 (MIC+) - Body ground

Always

10 kΩ or higher

J157-7 (MCI-) or U15-4 (MIC-) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

CHECK DCM (TELEMATICS TRANSCEIVER) (TELEPHONE MICROPHONE ASSEMBLY POWER SOURCE)

(a) Remove the telephone microphone assembly but do not disconnect the connectors.

Click here

*a

Component with harness connected

(Telephone Microphone Assembly)

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

U15-1 (MACC) - Body ground

Engine switch on (ACC)

4 to 6 V

Standard Resistance:

Tester Connection

Condition

Specified Condition

U15-4 (MIC-) - Body ground

Always

Below 1 Ω
OK

REPLACE TELEPHONE MICROPHONE ASSEMBLY

NG

4.

REPLACE DCM (TELEMATICS TRANSCEIVER)

(a) Replace the DCM (telematics transceiver) with a new one.

Click here

NOTICE:

  • The engine switch must be off
  • Do not exchange the DCM (telematics transceiver) with one from another vehicle.
NEXT

PERFORM DCM ACTIVATION

    Indicator (Green) Circuit Short to Ground (B157111,B157113)
    DESCRIPTION This DTC is set when the DCM (telematics transceiver) detects an open or short in the manual (SOS) switch green indicator circuit of the manual (SOS) switch. The manual (SOS) switch green ...

    DCM System Internal Failure (B15A804)
    DESCRIPTION This DTC is stored when an internal circuit malfunction is detected by the DCM (telematics transceiver) self check. DTC No. Detection Item DTC Detection Condition Trouble Area ...

    Other materials:

    Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Can Communication System: Check Bus 4 Line for Short to GND
    DESCRIPTION There may be a short circuit between one of the CAN bus lines and GND when there is no resistance between terminal 22 (CA2H) of the network gateway ECU and terminal 4 (CG) of the DLC3, or terminal 7 (CA2L) of the network gateway ECU and terminal 4 (CG) of the DLC3. Symptom Trouble A ...

    Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Cooling Fan System: Precaution
    PRECAUTION INITIALIZATION NOTICE: When the cable is disconnected from the negative (-) battery terminal, initialize the following system(s) after the cable is reconnected. System Name See Procedure Lane Control System Pre-Collision System Intelligent Clearance Sonar System ...

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual

    © 2025 Copyright www.lexusrx.net
    0.0145