DTC B15C4: Airbag Signal Malfunction/Not Input [06/2018 - 10/2019]: Procedure

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2024 Lexus ES 300h, 2023 Lexus ES 300h, 2022 Lexus ES 300h, 2021 Lexus ES 300h, and 2020 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.

CHECK DTC (AIRBAG SYSTEM)

Turn the power switch off.
Connect the Techstream to the DLC3.
Turn the power switch on (IG) and wait for 10 seconds.
Turn the Techstream on.

Check the DTC of "AIRBAG SYSTEM".

Refer to DTC CHECK / CLEAR [06/2018 - ]

Result

Result	Proceed to
DTCs are not output	A
DTCs are output	B

Result:

GO TO AIRBAG SYSTEM. Refer to DIAGNOSTIC TROUBLE CODE CHART [06/2018 - 08/2021]

Result:

See step 2

INSPECT DCM (TELEMATICS TRANSCEIVER) (GSW SIGNAL)

Remove the DCM (Telematics Transceiver) but do not disconnect the connectors.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*a	Component with harness connected (DCM (Telematics Transceiver))

Refer to REMOVAL [06/2018 - 10/2019]

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

Standard Voltage

Tester Connection	Condition	Specified Condition
G10-24 (GSW) - Body ground	Power switch on (IG)	6.5 to 8.5 V

Reference Waveform

Item	Condition
Tester connection	G10-24 (GSW) - Body ground
Tool setting	5.0 V/DIV., 20 ms/DIV.
Vehicle condition	Power switch on (IG)

Result

Result	Proceed to
8.5 V or higher	A
Below 6.5 V	B
6.5 to 8.5 V	C

Result:

See step 4

Result:

See step 5

Result:

See step 3

CHECK HARNESS AND CONNECTOR (FOR OPEN CIRCUIT)

Remove the airbag sensor assembly but do not disconnect the connectors.
Refer to REMOVAL [06/2018 - 08/2020]

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

Standard Voltage

Tester Connection	Condition	Specified Condition
G64-23 (GSW3) - Body ground	Power switch on (IG)	8.5 V or higher

Reference Waveform

Item	Condition
Tester connection	G64-23 (GSW3) - Body ground
Tool setting	5.0 V/DIV., 20 ms/DIV.
Vehicle condition	Power switch on (IG)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*a	Component with harness connected (Airbag Sensor Assembly)

Result

Proceed to
OK
NG

Result:

REPLACE AIRBAG ECU ASSEMBLY. Refer to REMOVAL [06/2018 - 10/2019]

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK HARNESS AND CONNECTOR (FOR SHORT CIRCUIT)

Disconnect the G10 DCM (Telematics Transceiver) connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
G10-24 (GSW) - Body ground	Always	10 kΩ or higher
G64-23 (GSW3) - Body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

Result:

See step 6

Result:

See step 5

REPLACE DCM (TELEMATICS TRANSCEIVER)

Replace the DCM (Telematics Transceiver).

Refer to REMOVAL [06/2018 - 10/2019]

NOTE:

The power switch must be off.
Do not swap the DCM (Telematics Transceiver) with one from another vehicle.

Result

Proceed to
NEXT

Result:

PERFORM DCM ACTIVATION. Refer to DCM ACTIVATION [06/2018 - 10/2019]

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

Disconnect the G10 DCM (Telematics Transceiver) connector.
Disconnect the G64 airbag sensor assembly connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
G10-24 (GSW) - G64-23 (GSW3)	Always	Below 1 Ω
G10-24 (GSW) - Body ground	Always	10 kΩ or higher
G64-23 (GSW3) - Body ground	Always	10 kΩ or higher

Result

Proceed to
OK
NG

Result:

REPLACE AIRBAG ECU ASSEMBLY. Refer to REMOVAL [06/2018 - 08/2020]

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR