Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Airbag Signal Signal Plausibility Failure (B15C464)

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Audio & Visual & Telematics / Cellular Communication / Safety Connect System / Airbag Signal Signal Plausibility Failure (B15C464)

DESCRIPTION

If the DCM (telematics transceiver) detects an error in communication between the DCM (telematics transceiver) and the airbag sensor assembly as a result of the DCM (telematics transceiver) self check, this DTC will be set.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B15C464

Airbag Signal Signal Plausibility Failure

DCM (telematics transceiver) detects an error in signals from airbag sensor assembly when engine switch is on (IG).
  • Airbag system
  • Harness or connector
  • Airbag sensor assembly
  • DCM (telematics transceiver)

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • The vehicle is equipped with an SRS (Supplemental Restraint System) which includes components such as airbags. Before servicing (including removal or installation of parts), be sure to read the Precaution in the SRS.

    Click here

  • After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

    Click here

PROCEDURE

1.

CHECK DTC (AIRBAG SYSTEM)

(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 > SRS Airbag > Clear DTCs

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

Body Electrical > SRS Airbag > Trouble Codes

OK:

No DTCs are output.

NG

GO TO AIRBAG SYSTEM

OK

2.

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

3.

CHECK DCM (TELEMATICS TRANSCEIVER) (GSW SIGNAL)

(a) Remove the DCM (telematics transceiver) but do not disconnect the connectors.

Click here

*a

Component with harness connected

(DCM (Telematics Transceiver))

(b) Check the input waveform.

(1) Check the signal waveform according to the condition(s) in the table below. (Check the waveform from the back of the wire harness connector of the DCM (telematics transceiver) while the airbag sensor assembly connectors are connected.)

Reference Waveform:

Item

Condition

Tester connection

J157-13 (GSW) - Body ground

Tool setting

5.0 V/DIV., 20 ms/DIV.

Vehicle condition

Engine switch on (IG)

OK:

The waveform is similar to that shown in the illustration.

NG

GO TO STEP 5

OK

4.

REPLACE DCM (TELEMATICS TRANSCEIVER)

(a) Replace the DCM (telematics transceiver).

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

5.

CHECK HARNESS AND CONNECTOR (DCM [TELEMATICS TRANSCEIVER] - AIRBAG SENSOR ASSEMBLY)

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

(b) Disconnect the J142 airbag sensor assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J157-13 (GSW) - J142-22 (GSW3)

Always

Below 1 Ω

J157-13 (GSW) - Body ground

Always

10 kΩ or higher
OK

REPLACE AIRBAG SENSOR ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
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