Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Emergency Call Switch Circuit Short to Ground (B15C511,B15C513)

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Audio & Visual & Telematics / Cellular Communication / Safety Connect System / Emergency Call Switch Circuit Short to Ground (B15C511,B15C513)

DESCRIPTION

If the DCM (telematics transceiver) detects an error in the communication between the DCM (telematics transceiver) and the map light assembly (manual (SOS) switch) as a result of the DCM (telematics transceiver) self check, this DTC will be stored.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

B15C511

Emergency Call Switch Circuit Short to Ground

Manual (SOS) switch impedance (Ω) is lower than the malfunction threshold for 10 seconds or more when the engine switch is on (IG)
  • Map light assembly (manual (SOS) switch)
  • Harness or connector
  • DCM (telematics transceiver)

B15C513

Emergency Call Switch Circuit Open

Manual (SOS) switch impedance (Ω) is higher than the malfunction threshold for 10 seconds or more when the engine switch is on (IG)
  • Map light assembly (manual (SOS) switch)
  • Harness or connector
  • DCM (telematics transceiver)

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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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.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

13 (SIG1) - 14 (GND3)

Manual (SOS) switch not operated

410 to 414 Ω

13 (SIG1) - 14 (GND3)

Manual (SOS) switch operated

81 to 83 Ω
NG

REPLACE MAP LIGHT ASSEMBLY (MANUAL (SOS) SWITCH)

OK

3.

CHECK HARNESS AND CONNECTOR (DCM (TELEMATICS TRANSCEIVER) - MAP LIGHT ASSEMBLY (MANUAL (SOS) SWITCH))

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

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J157-21 (SIG1) - U12-13 (SIG1)

Always

Below 1 Ω

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

Always

Below 1 Ω

J157-21 (SIG1) or U12-13 (SIG1) - Body ground

Always

10 kΩ or higher

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

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

REPLACE DCM (TELEMATICS TRANSCEIVER)

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

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NOTICE:

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