Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Emergency Call Switch Illumination Circuit

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Audio & Visual & Telematics / Cellular Communication / Safety Connect System / Emergency Call Switch Illumination Circuit

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.

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  • Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (MAP LIGHT ASSEMBLY (MANUAL (SOS) SWITCH) POWER SOURCE)

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

(b) Disconnect the U12 map light assembly (manual (SOS) switch) connector.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

U12-5 (RRID) - Body Ground

Engine switch on (IG)

11 to 14 V

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J157-3 (SIG-) - U12-9 (GND3)

Always

Below 1 Ω

J157-3 (SIG-) or U12-9 (GND3) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

2.

INSPECT MAP LIGHT ASSEMBLY (MANUAL (SOS) SWITCH)

(a) Remove the map light assembly (manual (SOS) switch).

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*a

Component without harness connected

(Map Light Assembly (Manual (SOS) Switch))

(b) Apply battery voltage to the connector and check that the roof console box assembly comes on.

OK:

Measurement Condition

Condition

Specified Condition

Battery positive (+) → U12-5 (RRID)

Battery negative (-) → U12-9 (GND3)

Always

Manual (SOS) switch illumination cones on
NG

REPLACE MAP LIGHT ASSEMBLY (MANUAL (SOS) SWITCH)

OK

3.

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

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