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

DESCRIPTION

After the combination meter assembly has started, the combination meter 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 combination meter 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 combination meter 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

CAUTION / NOTICE / HINT

NOTICE:

When replacing the combination meter assembly, always replace it with a new one. If a combination meter assembly which was installed to another vehicle is used, the information stored in it will not match the information from the vehicle and a DTC may be stored.

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.	CONFIRM MODEL

(a) Choose the model to be inspected.

Result	Proceed to
w/ Headup Display System	A
w/o Headup Display System	B

B

GO TO STEP 6

A

5.	CHECK FOR DTC (HEADUP DISPLAY SYSTEM)

(a) Check if headup display system DTCs are output.

Body Electrical > Head Up Display > Trouble Codes

Result	Proceed to
DTC B1321 is not output	A
DTC B1321 is output	B

A

REPLACE COMBINATION METER ASSEMBLY

B

REPLACE RADIO RECEIVER ASSEMBLY

6.	REPLACE COMBINATION METER ASSEMBLY

(a) Replace the combination meter assembly with a new one.

Click here

NEXT

7.	CHECK FOR DTC (METER / GAUGE SYSTEM)

(a) Turn the engine switch on (IG).

(b) Wait 30 seconds or more.

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

Body Electrical > Combination Meter > Trouble Codes

Result	Proceed to
DTC B1321 is not output	A
DTC B1321 is output	B

A

END (COMBINATION METER ASSEMBLY WAS DEFECTIVE)

B

REPLACE RADIO RECEIVER ASSEMBLY