Lexus NX: Back Door Closer does not Operate

DESCRIPTION

When the back door closer does not operate, one of the following may be the cause: 1) improper fit of the back door, or a foreign object is stuck in the back door, 2) a malfunction in the multiplex network door ECU power source circuit, 3) a malfunction in the back door lock assembly circuit, or 4) a malfunction in the multiplex network door ECU.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • First perform the communication function inspections in How to Proceed with Troubleshooting to confirm that there are no CAN communication malfunctions before troubleshooting this problem.

    Click here

  • Inspect fuses for circuits related to this system before performing the following inspection procedure.
  • If the replacement, removal and installation of the multiplex network door ECU or disconnection of the connectors of the multiplex network door ECU has been performed, initialize the power back door system.

    Click here

  • Recognition code registration is necessary when replacing the main body ECU (multiplex network body ECU).
  • If the main body ECU (multiplex network body ECU) is replaced, refer to Registration.

    Click here

PROCEDURE

1.

CHECK FOR DTC

(a) Check for DTCs.

Click here

Body Electrical > Back Door > Trouble Codes

Result

Proceed to

DTC is not output

A

DTC B2250 is output

B

DTC B2251 is output

C

B

GO TO DTC B2250

C

GO TO DTC B2251

A

2.

CHECK BACK DOOR LOCK FUNCTION

(a) Check if the back door can be fully closed by hand.

Result

Proceed to

The back door can be closed normally

A

The back door cannot be closed normally

B

B

IMPROPER FIT OF BACK DOOR, OR A FOREIGN OBJECT IS STUCK IN BACK DOOR

A

3.

CHECK HARNESS AND CONNECTOR (MULTIPLEX NETWORK DOOR ECU -BATTERY AND BODY GROUND)

(a) Disconnect the multiplex network door ECU connectors.

*a

Rear view of wire harness connector

(to Multiplex Network Door ECU)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Y27-10 (GND) - Body ground

Always

Below 1 Ω

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

Y26-20 (ECUB) - Body ground

Power switch off

11 to 14 V

Y27-1 (B) - Body ground

Power switch off

11 to 14 V

Y26-18 (IG) - Body ground

Power switch on (IG)

11 to 14 V

Power switch off

Below 1 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.

INSPECT BACK DOOR LOCK ASSEMBLY

(a) Remove the back door lock assembly.

Click here

(b) Inspect the back door lock assembly.

Click here

NG

REPLACE BACK DOOR LOCK ASSEMBLY

OK

5.

CHECK HARNESS AND CONNECTOR (BACK DOOR LOCK ASSEMBLY - MULTIPLEX NETWORK DOOR ECU AND BODY GROUND)

(a) Disconnect the Y12 back door lock assembly connector.

(b) Disconnect the Y26 and Y27 multiplex network door ECU connectors.

(c) Disconnect the 4A instrument panel junction block assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Y12-1 (M+) - Y27-4 (DC+)

Always

Below 1 Ω

Y12-4 (M-) - Y27-3 (DC-)

Always

Below 1 Ω

Y12-8 (CTY) - Y26-11 (FUL)

Always

Below 1 Ω

Y12-2 (FSW) - Y26-13 (PAWL)

Always

Below 1 Ω

Y12-3 (CLS) - Y26-9 (HAF)

Always

Below 1 Ω

Y12-6 (OPN) - Y26-7 (POS)

Always

Below 1 Ω

Y12-7 (E) - Body ground

Always

Below 1 Ω

Y12-1 (M+) or Y27-4 (DC+) - Body ground

Always

10 kΩ or higher

Y12-4 (M-) or Y27-3 (DC-) - Body ground

Always

10 kΩ or higher

Y12-2 (FSW) or Y26-13 (PAWL) - Body ground

Always

10 kΩ or higher

Y12-8 (CTY) or Y26-11 (FUL) - Body ground

Always

10 kΩ or higher

Y12-3 (CLS) or Y26-9 (HAF) - Body ground

Always

10 kΩ or higher

Y12-6 (OPN) or Y26-7 (POS) - Body ground

Always

10 kΩ or higher

OK

REPLACE MULTIPLEX NETWORK DOOR ECU

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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