Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Power Back Door Warning System does not Operate

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Vehicle Exterior / Door / Hatch / Power Back Door System (w/ Outside Door Control Switch) / Power Back Door Warning System does not Operate

DESCRIPTION

If the power back door warning system does not operate, there may be a malfunction in one of the following: 1) wireless door lock control system, 2) power back door warning buzzer circuit or 3) multiplex network door ECU.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • If the multiplex network door ECU has been removed and installed or replaced, or if any of the connectors have been disconnected, initialize the power back door system.

    Click here

  • The PBD Buzzer can be customized. Make sure the function is set to ON.

    Click here

  • If the main body ECU (multiplex network body ECU) is replaced, refer to Registration.

    Click here

PROCEDURE

1.

CHECK OPERATION

(a) Check power back door system operation.

Click here

Result

Proceed to

Hazard warning light does not come on (w/ Power Back Door Hazard Warning Light)

A

Power back door warning buzzer does not operate

B
B

GO TO STEP 6

A

2.

CHECK WIRELESS DOOR LOCK CONTROL SYSTEM (HAZARD ANSWER-BACK FUNCTION)

(a) Check wireless door lock operation.

Click here

OK:

Hazard answer-back function operates normally.

NG

GO TO WIRELESS DOOR LOCK CONTROL SYSTEM

OK

3.

REPLACE MULTIPLEX NETWORK DOOR ECU

(a) Temporarily replace the multiplex network door ECU with a new or known good one.

Click here

NEXT

4.

INITIALIZE POWER BACK DOOR SYSTEM

(a) Perform initialize the power back door system.

Click here

NEXT

5.

CHECK POWER BACK DOOR SYSTEM

(a) Check that the power back door hazard warning lights operate normally.

Click here

OK:

The power back door hazard warning lights operate normally.

OK

END (MULTIPLEX NETWORK DOOR ECU WAS DEFECTIVE)
NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

6.

PERFORM ACTIVE TEST USING TECHSTREAM (PBD BUZZER)

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Back Door / Data List.

(e) Perform the Active Test according to the display on the Techstream.

Body Electrical > Back Door > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

PBD Buzzer

Power back door warning buzzer sound

OFF or ON

-
Body Electrical > Back Door > Active Test

Tester Display

PBD Buzzer

OK:

Power back door warning buzzer sounds

OK

REPLACE MULTIPLEX NETWORK DOOR ECU

NG

7.

CHECK HARNESS AND CONNECTOR (POWER BACK DOOR WARNING BUZZER - MULTIPLEX NETWORK DOOR ECU AND BODY GROUND)

(a) Disconnect the Z24 power back door warning buzzer connector.

(b) Disconnect the Z16 multiplex network door ECU connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Z24-1 (BZR+) - Z16-16 (BZR+)

Always

Below 1 Ω

Z24-2 (BZR-) - Body ground

Always

Below 1 Ω

Z24-1 (BZR+) or Z16-16 (BZR+) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

8.

REPLACE POWER BACK DOOR WARNING BUZZER

(a) Replace the power back door warning buzzer with a new or known good one.

Click here

NEXT

9.

CHECK POWER BACK DOOR WARNING SYSTEM

(a) Check that the power back door warning buzzer operates normally.

Click here

OK:

Power back door warning buzzer sounds

OK

END (POWER BACK DOOR WARNING BUZZER WAS MALFUNCTIONING)
NG

REPLACE MULTIPLEX NETWORK DOOR ECU

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