Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Lost Communication with EMV (B1321)

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Vehicle Interior / Meter / Gauge / Display / Headup Display System / Lost Communication with EMV (B1321)

DESCRIPTION

After the headup display (meter mirror sub-assembly) has started, the headup display (meter mirror sub-assembly) attempts to detect the radio receiver assembly by performing communication via local bus.

This DTC is stored when the radio receiver assembly has been detected but communication between the headup display (meter mirror sub-assembly) and radio receiver assembly is interrupted.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

Note

B1321

Lost Communication with EMV

Diagnosis Condition:

  • The headup display (meter mirror sub-assembly) has started
  • The radio receiver assembly has started

Malfunction Status:

  • After the radio receiver assembly is detected, communication via local bus is interrupted

Malfunction Time:

  • 30 seconds or more
  • Radio receiver assembly
  • Harness or connector
  • Combination meter assembly

DTC stored

-

WIRING DIAGRAM

PROCEDURE

1.

CONFIRM MODEL

(a) Choose the model to be inspected.

Result

Proceed to

w/o Navigation System

A

w/ Navigation System

B
B

GO TO STEP 3

A

2.

CHECK FOR DTC (AUDIO AND VISUAL SYSTEM)

(a) Check if audio and visual system DTCs are output.

Body Electrical > Navigation System > Trouble Codes

Result

Proceed to

DTCs are not output

A

DTCs are output

B
A

GO TO STEP 4

B

GO TO AUDIO AND VISUAL SYSTEM

3.

CHECK FOR DTC (NAVIGATION SYSTEM)

(a) Check if navigation system DTCs are output.

Body Electrical > Navigation System > Trouble Codes

Result

Proceed to

DTCs are not output

A

DTCs are output

B
B

GO TO NAVIGATION SYSTEM

A

4.

CHECK FOR DTC (METER / GAUGE SYSTEM)

(a) Check if meter / gauge system DTCs are output.

Body Electrical > Combination Meter > Trouble Codes

HINT:

  • If DTC B1321 is output from the headup display system and is not output from the meter / gauge system, it can be suspected that the headup display (meter mirror sub-assembly) has an internal malfunction.
  • If DTC B1321 is output from the meter / gauge system and is not output from the audio and visual system or navigation system, it can be suspected that the radio receiver assembly has an internal malfunction.

Result

Proceed to

DTCs are not output

A

DTCs are output

B
A

REPLACE HEADUP DISPLAY (METER MIRROR SUB-ASSEMBLY)

B

REPLACE RADIO RECEIVER ASSEMBLY

    Diagnostic Trouble Code Chart
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    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual

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