Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual: DCM Data Signal Circuit between Navigation ECU and DCM

DESCRIPTION

This circuit is used to send and receive signals between the DCM (Telematics Transceiver), radio receiver assembly and navigation ECU.

WIRING DIAGRAM

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - DCM (TELEMATICS TRANSCEIVER))

(a) Disconnect the J157 DCM (Telematics Transceiver) connector.

(b) Disconnect the J149 radio receiver assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J157-31 (USBG) - J149-11 (USBG)

Always

Below 1 Ω

J157-17 (VOT+) - J149-13 (VOR+)

Always

Below 1 Ω

J157-15 (USBV) - J149-10 (USBV)

Always

Below 1 Ω

J157-17 (VOT-) - J149-14 (VOR-)

Always

Below 1 Ω

J157-34 (VOR-) - J149-16 (VOT-)

Always

Below 1 Ω

J157-18 (VOR+) - J149-15 (VOT+)

Always

Below 1 Ω

J157-31 (USBG) or J149-11 (USBG) - Body ground

Always

10 kΩ or higher

J157-17 (VOT+) or J149-13 (VOR+) - Body ground

Always

10 kΩ or higher

J157-15 (USBV) or J149-10 (USBV) - Body ground

Always

10 kΩ or higher

J157-17 (VOT-) or J149-14 (VOR-) - Body ground

Always

10 kΩ or higher

J157-34 (VOR-) or J149-16 (VOT-) - Body ground

Always

10 kΩ or higher

J157-18 (VOR+) or J149-15 (VOT+) - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

2.

CHECK HARNESS AND CONNECTOR (NAVIGATION ECU - DCM (TELEMATICS TRANSCEIVER))

(a) Disconnect the J157 DCM (Telematics Transceiver) connector.

*a

Front view of wire harness connector

(to DCM (Telematics Transceiver))

*b

Front view of wire harness connector

(to Navigation ECU)

(b) Disconnect the J153 navigation ECU connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J157-1 (USB-) - J153-2 (USB-)

Always

Below 1 Ω

J157-2 (USB+) - J153-1 (USB+)

Always

Below 1 Ω

J157-3 (USBS) - J153-3(USBS)

Always

Below 1 Ω

J157-1 (USB-) or J153-2 (USB-) - Body ground

Always

10 kΩ or higher

J157-2 (USB+) or J153-1 (USB+) - Body ground

Always

10 kΩ or higher

J157-3 (USBS) or J153-3 (USBS) - Body ground

Always

10 kΩ or higher

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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