Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Rear Door LH Entry Unlock Function does not Operate

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Access System With Push-button Start (for Entry Function) / Rear Door LH Entry Unlock Function does not Operate

DESCRIPTION

If the entry unlock function does not operate for the rear door LH only, but the entry lock function operates, the request code is being transmitted properly from the rear door LH. In this case, there may be a problem related to the unlock sensor (connection between the certification ECU (smart key ECU assembly) and rear door outside handle assembly LH).

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • The smart access system with push-button start (for Entry Function) uses the LIN communication system and CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting. Troubleshoot the smart access system with push-button start (for Entry Function) after confirming that the communication systems are functioning properly.

    Click here

  • When using the Techstream with the engine switch off, connect the Techstream to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and the vehicle begins. Then select the vehicle type under manual mode and enter the following menus: Body Electrical / Smart Access. While using the Techstream, periodically turn a courtesy light switch on and off at intervals of 1.5 seconds or less to maintain communication between the Techstream and the vehicle.
  • Check that there are no electrical key transmitter sub-assemblies in the vehicle.
  • Before replacing the certification ECU (smart key ECU assembly), refer to Precaution.

    Click here

  • After repair, confirm that no DTCs are output.

PROCEDURE

1.

CHECK POWER DOOR LOCK CONTROL SYSTEM

(a) When the door control switch on the multiplex network master switch assembly is operated, check that the doors unlock and lock according to the switch operation.

Click here

OK:

Door locks operate normally.

NG

GO TO POWER DOOR LOCK CONTROL SYSTEM

OK

2.

READ VALUE USING TECHSTREAM (RL-DOOR LOCK POS SW)

(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 / Main Body / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Main Body > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

RL-Door Lock Pos SW

Rear door LH unlock detection switch signal

ON or OFF

ON: Rear door LH unlocked

OFF: Rear door LH locked

-
Body Electrical > Main Body > Data List

Tester Display

RL-Door Lock Pos SW

OK:

The Techstream display changes correctly in response to the lock/unlock operation of the rear door LH.

NG

GO TO LIGHTING SYSTEM (Proceed to Door Unlock Detection Switch Circuit)

OK

3.

READ VALUE USING TECHSTREAM (DR-DOOR TOUCH SENSOR)

(a) Turn the engine switch off.

(b) Open and close the rear door LH.

(c) With the electrical key transmitter sub-assembly outside of the vehicle, press the lock switch of the electrical key transmitter sub-assembly to lock all of the doors.

(d) Hold the electrical key transmitter sub-assembly at the same height as the door outside handle assembly and approximately 0.3 m (0.984 ft.) from the rear door LH.

(e) Check that the LED of the electrical key transmitter sub-assembly blinks.

(f) Read the Data List according to the display on the Techstream.

(g) Touch the unlock sensor on the backside of the front door outside handle assembly (for rear door LH).

HINT:

When checking the operation of the unlock sensor again, make sure to perform the procedure from step (a).

Body Electrical > Smart Access > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Dr-Door Touch Sensor

Rear door LH touch sensor (unlock sensor)

ON or OFF

ON: Rear door LH touch sensor (unlock sensor) touched

OFF: Rear door LH touch sensor (unlock sensor) not touched
  • Displays whether the unlock sensor is on or off (even if the sensor is touched and contact is maintained, "ON" is displayed only momentarily).
  • Use this Data List item to help determine if there is an unlock sensor malfunction when the entry unlock function does not operate.
Body Electrical > Smart Access > Data List

Tester Display

Dr-Door Touch Sensor

OK:

The Techstream display changes correctly in response to the operation of the rear door outside handle assembly LH.

*a

Unlock Sensor (Backside)
OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

4.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - REAR DOOR OUTSIDE HANDLE ASSEMBLY LH)

(a) Disconnect the R1 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the P4 rear door outside handle assembly LH connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

R1-1 (CLG3) - P4-4 (ANT1)

Always

Below 1 Ω

R1-2 (CG3B) - P4-5 (ANT2)

Always

Below 1 Ω

R1-1 (CLG3) or P4-4 (ANT1) - Body ground

Always

10 kΩ or higher

R1-2 (CG3B) or P4-5 (ANT2) - Body ground

Always

10 kΩ or higher

(d) Reconnect the P4 rear door outside handle assembly LH connector.

(e) Reconnect the R1 certification ECU (smart key ECU assembly) connector.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

CHECK REAR DOOR OUTSIDE HANDLE ASSEMBLY LH (INPUT TO CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))

*a

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))

*b

Waveform 1

*c

Unlock sensor not touched

*d

Unlock sensor touched

(a) Using an oscilloscope, check the waveform.

OK:

Tester Connection

Condition

Tool Setting

Specified Condition

R1-1 (CLG3) - J41-18 (E)

Procedure:

  1. Engine switch off
  2. Electrical key transmitter sub-assembly brought outside vehicle
  3. All doors locked
  4. Electrical key transmitter sub-assembly not near the vehicle
  5. Rear door LH unlock sensor touched

5 V/DIV., 50 ms/DIV.

Pulse generation

(See waveform 1)
OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

REPLACE REAR DOOR OUTSIDE HANDLE ASSEMBLY LH

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