Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual: All Door Entry Lock/Unlock Functions and Wireless Functions do not Operate

Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Access System With Push-button Start (for Entry Function) / All Door Entry Lock/Unlock Functions and Wireless Functions do not Operate

DESCRIPTION

If the entry lock and wireless door lock operations cannot be performed, the door control receiver may be malfunctioning, or there may be wave interference or problems in the communication which is used for the entry and wireless function between the door control receiver and certification ECU (smart key ECU assembly).

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.
Before replacing the certification ECU (smart key ECU assembly) or main body ECU (multiplex network body ECU), refer to Precaution.
Click here
After repair, confirm that no DTCs are output.
Inspect the fuses for circuits related to this system before performing the following procedure.
Check that there are no electrical key transmitter sub-assemblies in the vehicle.
Before performing the inspection, check that DTC B1242 (wireless door lock control) is not output.
Click here
When replacing the door control receiver, read the transmitter IDs (tire pressure warning system) stored in the old ECU using the Techstream and write them down before removal.
Click here
It is necessary to perform initialization (Click here ) after registration (Click here ) of the transmitter IDs into the door control receiver if the door control receiver has been replaced.

PROCEDURE

1.	INSPECT BATTERY VOLTAGE

(a) Measure the battery voltage with the engine switch off.

Standard Voltage:

11 to 14 V

HINT:

It may be possible to tell whether the battery is discharged by operating the horn.

If the voltage is below 11 V, recharge or replace the battery before proceeding to the next step.

2.	CHECK FOR DTC

(a) Open the driver door using the mechanical key built into the electrical key transmitter sub-assembly.

(b) Check for DTCs.

Body Electrical > Smart Access > Trouble Codes

Result	Proceed to
DTCs are not output	A
DTCs are output	B

GO TO DIAGNOSTIC TROUBLE CODE CHART

3.	CHECK DOOR AJAR WARNING

(a) When the doors are locked by operating the entry lock function with all doors closed, check that the door ajar warning operates.

HINT:

Make sure to set the customize setting Open Door Warning to ON before performing this inspection.
Warning function (door ajar warning)
Click here

Result	Proceed to
The wireless buzzer does not sound	A
The wireless buzzer sounds	B

GO TO LIGHTING SYSTEM (Proceed to Door Courtesy Switch Circuit)

4.	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

Result	Proceed to
Power door lock function operates normally	A
Power door lock function does not operate normally	B

GO TO POWER DOOR LOCK CONTROL SYSTEM

5.	CHECK KEY DIAGNOSTIC MODE

(a) Check the following antennas in key diagnostic mode.

Body Electrical > Smart Access > Utility

Tester Display
Communication Check(Key Diag Mode)

(1) Check the electrical key antenna (for driver door):

When the electrical key transmitter sub-assembly is brought within 0.7 to 1 m (2.30 to 3.28 ft.) of the front door outside handle assembly (for driver door), check that the wireless buzzer sounds.

HINT:

Select either channel 1 or channel 2 and perform the key diagnostic mode inspection for each channel.
If the buzzer sounds with [CH1] displayed but not with [CH2], the electrical key transmitter sub-assembly cannot be detected by channel 2 due to a malfunction, such as wave interference.

*a	0.7 to 1 m (2.30 to 3.28 ft.)

(2) Check the electrical key antenna (for front passenger door):

When the electrical key transmitter sub-assembly is brought within 0.7 to 1 m (2.30 to 3.28 ft.) of the front door outside handle assembly (for front passenger door), check that the wireless buzzer sounds.

HINT:

Select either channel 1 or channel 2 and perform the key diagnostic mode inspection for each channel.
If the buzzer sounds with [CH1] displayed but not with [CH2], the electrical key transmitter sub-assembly cannot be detected by channel 2 due to a malfunction, such as wave interference.

*a	0.7 to 1 m (2.30 to 3.28 ft.)

(3) Check the electrical key antenna (for rear door (for driver side)):

When the electrical key transmitter sub-assembly is brought within 0.7 to 1 m (2.30 to 3.28 ft.) of the rear door outside handle assembly (for driver side), check that the wireless buzzer sounds.

HINT:

Select either channel 1 or channel 2 and perform the key diagnostic mode inspection for each channel.
If the buzzer sounds with [CH1] displayed but not with [CH2], the electrical key transmitter sub-assembly cannot be detected by channel 2 due to a malfunction, such as wave interference.

*a	0.7 to 1 m (2.30 to 3.28 ft.)

(4) Check the electrical key antenna (for rear door (for front passenger side)):

When the electrical key transmitter sub-assembly is brought within 0.7 to 1 m (2.30 to 3.28 ft.) of the rear door outside handle assembly (for front passenger side), check that the wireless buzzer sounds.

HINT:

Select either channel 1 or channel 2 and perform the key diagnostic mode inspection for each channel.
If the buzzer sounds with [CH1] displayed but not with [CH2], the electrical key transmitter sub-assembly cannot be detected by channel 2 due to a malfunction, such as wave interference.

*a	0.7 to 1 m (2.30 to 3.28 ft.)

(5) Check the No. 1 indoor electrical key antenna assembly (front floor):

When the electrical key transmitter sub-assembly is at either inspection point, check that the wireless buzzer sounds.

HINT:

Select either channel 1 or channel 2 and perform the key diagnostic mode inspection for each channel.
If the buzzer sounds with [CH1] displayed but not with [CH2], the electrical key transmitter sub-assembly cannot be detected by channel 2 due to a malfunction, such as wave interference.

*a	Inspection Point

(6) Check the No. 2 indoor electrical key antenna assembly (rear floor):

When the electrical key transmitter sub-assembly is at either inspection point, check that the wireless buzzer sounds.

HINT:

Select either channel 1 or channel 2 and perform the key diagnostic mode inspection for each channel.
If the buzzer sounds with [CH1] displayed but not with [CH2], the electrical key transmitter sub-assembly cannot be detected by channel 2 due to a malfunction, such as wave interference.

*a	Inspection Point

(7) Check the No. 3 indoor electrical key antenna assembly (inside luggage compartment):

When the electrical key transmitter sub-assembly is at either inspection point, check that the wireless buzzer sounds.

HINT:

Select either channel 1 or channel 2 and perform the key diagnostic mode inspection for each channel.
If the buzzer sounds with [CH1] displayed but not with [CH2], the electrical key transmitter sub-assembly cannot be detected by channel 2 due to a malfunction, such as wave interference.

*a	Inspection Point

(8) Check the electrical key antenna (outside luggage compartment):

When the electrical key transmitter sub-assembly is brought within 0.7 to 1 m (2.30 to 3.28 ft.) of the electrical key antenna (outside luggage compartment), check that the wireless buzzer sounds.

HINT:

Select either channel 1 or channel 2 and perform the key diagnostic mode inspection for each channel.
If the buzzer sounds with [CH1] displayed but not with [CH2], the electrical key transmitter sub-assembly cannot be detected by channel 2 due to a malfunction, such as wave interference.

OK:

Wireless buzzer sounds.

*a	0.7 to 1 m (2.30 to 3.28 ft.)

Result	Proceed to
Key diagnostic mode inspections fail for both channels	A
Key diagnostic mode inspections succeed for both channels	B
Key diagnostic mode inspection succeeds for only one of the channels	C

GO TO STEP 18

GO TO STEP 28

6.	CHECK WAVE ENVIRONMENT

(a) Bring the electrical key transmitter sub-assembly near the door control receiver and perform a wireless operation 2 or more times*.

*: When the wireless function is operated, channel 1 and 2 are used alternately. If the first wireless operation is performed successfully and the second wireless operation fails, wave interference may be occurring for either channel.

HINT:

When the electrical key transmitter sub-assembly is brought near the door control receiver, the possibility of wave interference decreases, and it can be determined if wave interference is causing the problem symptom.
If the inspection result is that the problem only occurs in certain locations or at certain times of day, the possibility of wave interference is high. Also, added vehicle components may cause wave interference. If installed, remove them and perform the operation check.
There may be wave interference if the vehicle is near broadcasting antennas, large video displays, wireless garage door opener systems, wireless security cameras, home security systems, etc. In this case, move the vehicle to a different location and check if there is any improvement.
If a tool for checking radio waves, such as a signal strength meter, is available, move around the area while observing both the LF band (used by the vehicle antenna to form the detection area) and RF band (used by the electrical key transmitter sub-assembly for transmission) to check for locations where there is wave interference.

Result	Proceed to
Wireless function does not operate normally	A
Wireless function operates normally	B

AFFECTED BY WAVE INTERFERENCE

7.	CHECK TRANSMITTER BATTERY

(a) Check the transmitter battery level of the electrical key transmitter sub-assembly that was checked first.

(1) Press and hold the lock switch of the electrical key transmitter sub-assembly for 5 seconds and check the number of times that the LED illuminates.

HINT:

The electrical key transmitter sub-assembly sends voltage information to the certification ECU (smart key ECU assembly) when it is being used. "Yes" is displayed for the Data List item "Key Low Battery" when this voltage information indicates 2.2 V or less.
Click here
Even if the transmitter battery is depleted, it is still possible to start the engine by holding the electrical key transmitter sub-assembly near the engine switch, depressing the brake pedal and pressing the engine switch.

Result	Proceed to
LED illuminates 3 times or more when switch is pressed and held	A
LED does not illuminate when switch is pressed and held	B
LED illuminates once or twice but not a third time	C

GO TO STEP 17

REPLACE TRANSMITTER BATTERY

8.	CHECK ELECTRICAL KEY TRANSMITTER SUB-ASSEMBLY

(a) Check if there is another electrical key transmitter sub-assembly available that is already registered to the vehicle.

Result	Proceed to
Another registered electrical key transmitter sub-assembly is not available	A
Another registered electrical key transmitter sub-assembly is available	B

GO TO STEP 10

9.	ELECTRICAL KEY TRANSMITTER SUB-ASSEMBLY REGISTRATION (NEW ELECTRICAL KEY TRANSMITTER SUB-ASSEMBLY)

(a) Register a new electrical key transmitter sub-assembly.

Click here

10.	CHECK ENTRY LOCK OPERATION

(a) Using another registered electrical key transmitter sub-assembly, check that the function operates normally.

Result	Proceed to
Entry function does not operate normally	A
Entry function operates normally	B

END (ELECTRICAL KEY TRANSMITTER SUB-ASSEMBLY WAS DEFECTIVE)

11.	CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - DOOR CONTROL RECEIVER AND BODY GROUND)

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

(b) Disconnect the R23 door control receiver connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
R1-18 (RCO) - R23-8 (+5)	Always	Below 1 Ω
R1-19 (RDAM) - R23-2 (DATA)	Always	Below 1 Ω
R1-20 (CSEL) - R23-6 (CSEL)	Always	Below 1 Ω
R23-12 (GND) - Body ground	Always	Below 1 Ω
R1-18 (RCO) or R23-8 (+5) - Body ground	Always	10 kΩ or higher
R1-19 (RDAM) or R23-2 (DATA) - Body ground	Always	10 kΩ or higher
R1-20 (CSEL) or R23-6 (CSEL) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

12.	CHECK ENTRY LOCK OPERATION

(a) Connect all connectors and check that the function operates normally.

Click here

Result	Proceed to
Entry function does not operate normally	A
Entry function operates normally	B

END (CONNECTOR WAS NOT CONNECTED SECURELY)

13.	CHECK DOOR CONTROL RECEIVER

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
R23-12 (GND) - Body ground	Always	Below 1 Ω

(b) Using an oscilloscope, check the waveform.

OK:

Tester Connection

Condition

Tool Setting

Specified Condition

R23-2 (DATA) - R23-12 (GND)

Procedure:

Engine switch off
All doors locked
Electrical key transmitter sub-assembly not inside vehicle
Electrical key transmitter sub-assembly brought outside detection area but kept inside wireless function operational area
Lock or unlock switch of electrical key transmitter sub-assembly not pressed → pressed

5 V/DIV., 500 ms/DIV.

Below 1 V → Pulse generation

(See waveform 1)

*a	Component with harness connected (Door Control Receiver)
*b	Waveform 1
*c	Before lock or unlock switch of electrical key transmitter sub-assembly pressed
*d	After lock or unlock switch of electrical key transmitter sub-assembly pressed

REPLACE DOOR CONTROL RECEIVER

14.	CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
R23-1 (IG) - R23-12 (GND)	Engine switch on (IG)	10 to 16 V
R23-6 (CSEL) - R23-12 (GND)	Procedure: Engine switch off All doors closed	Below 1 V → Pulse generation

*a	Component with harness connected (Door Control Receiver)

(b) Using an oscilloscope, check the waveform.

OK:

Tester Connection

Condition

Tool Setting

Specified Condition

R23-8 (+5) - R23-12 (GND)

Procedure:

Engine switch off
Electrical key transmitter sub-assembly brought outside detection area but kept inside wireless function operational area
Lock or unlock switch of electrical key transmitter sub-assembly not pressed → pressed

2 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform 1)

*a	Component with harness connected (Door Control Receiver)
*b	Waveform 1
*c	Before lock or unlock switch of electrical key transmitter sub-assembly pressed
*d	After lock or unlock switch of electrical key transmitter sub-assembly pressed

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

15.	REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

(a) Replace the certification ECU (smart key ECU assembly) and perform registration again.

HINT:

For replacement.
Click here
For registration.
Click here

16.	CHECK WIRELESS DOOR LOCK CONTROL SYSTEM

(a) Check that the wireless function operates normally.

Click here

Result	Proceed to
Wireless door lock function operates normally	A
Wireless door lock function does not operate normally	B

END (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) WAS DEFECTIVE)

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

17.	INSPECT TRANSMITTER BATTERY

(a) Inspect the transmitter battery.

Click here

NOTICE:

Do not wrap the lead wire around a terminal, wedge it between terminals, or solder it. The terminal may be deformed or damaged, and the transmitter battery will not be able to be installed correctly.

REPLACE ELECTRICAL KEY TRANSMITTER SUB-ASSEMBLY

REPLACE TRANSMITTER BATTERY

18.	PERFORM REGISTRATION

(a) Perform registration of the B code.

Click here

19.	CHECK ENTRY LOCK OPERATION

(a) After completing B code registration, check that the entry lock and unlock functions can be operated 2 times consecutively.

Click here

Result	Proceed to
Entry function does not operate normally	A
Entry function operates normally	B

END (B CODE REGISTRATION FAILED)

20.	READ VALUE USING TECHSTREAM (B CODE)

(a) Connect the Techstream to the DLC3.

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

(d) Enter the following menus: Body Electrical / Smart Access / Data List.

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

Body Electrical > Smart Access > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

B Code

B code registration status

Regd or No Regd

Regd: B code registered correctly

No Regd: B code not registered correctly

Body Electrical > Smart Access > Data List

Tester Display
B Code

Result	Proceed to
"No Regd" is displayed on the Techstream	A
"Regd" is displayed on the Techstream	B

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

21.	READ VALUE USING TECHSTREAM (B CODE DIFFERENCE)

(a) Connect the Techstream to the DLC3.

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

(d) Enter the following menus: Body Electrical / Smart Access / Data List.

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

Body Electrical > Smart Access > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

B Code Difference

B code mismatch

Yes or No

Yes: Communication malfunction

No: Communication normal

Body Electrical > Smart Access > Data List

Tester Display
B Code Difference

Result	Proceed to
"No" is displayed on the Techstream	A
"Yes" is displayed on the Techstream	B

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

22.	CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

(a) Measure the voltage while checking the Data List on the Techstream.

(1) Connect the Techstream to the DLC3.

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

(3) Turn the Techstream on.

(4) Enter the following menus: Body Electrical / Power Source Control / Data List.

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

Component with harness connected

(Certification ECU (Smart Key ECU Assembly))

Body Electrical > Power Source Control > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Power Supply Condition

Power supply state

All OFF, ACC ON, IG ON or ST ON

All OFF: Engine switch off

ACC ON: Engine switch on (ACC)

IG ON: Engine switch on (IG)

ST ON: Sending engine start request signal

Body Electrical > Power Source Control > Data List

Tester Display
Power Supply Condition

Standard Voltage:

Tester Connection	Condition	Specified Condition
J41-17 (IG1D) - Body ground	Engine switch off	Below 1 V
	Engine switch on (ACC)	Below 1 V
	Engine switch on (IG)	9 V or higher
J41-16 (ACCD) - Body ground	Engine switch off	Below 1 V
	Engine switch on (ACC)	9 V or higher
	Engine switch on (IG)	9 V or higher

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

23.	READ VALUE USING TECHSTREAM (ACC SW, IG SW)

(a) Connect the Techstream to the DLC3.

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

(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

ACC SW

Engine switch status

ON or OFF

ON: Engine switch on (ACC)

OFF: Engine switch off

"ON" is also displayed when the engine switch is on (IG).

IG SW

Engine switch status

ON or OFF

ON: Engine switch on (IG)

OFF: Engine switch off

"OFF" is also displayed when the engine switch is on (ACC).

Body Electrical > Main Body > Data List

Tester Display
ACC SW
IG SW

HINT:

If the certification ECU (smart key ECU assembly) misjudges for any reason that the engine switch is on (IG) even though the engine switch is off, the entry lock and unlock functions will be disabled.

Result	Proceed to
The main body ECU (multiplex network body ECU) judges properly that the power source is off when the engine switch is off	A
The main body ECU (multiplex network body ECU) does not judge properly that the power source is off when the engine switch is off	B

TROUBLESHOOT MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

24.	CHECK HARNESS AND CONNECTOR (BODY GROUND, POWER SUPPLY)

(a) Disconnect the J41 certification ECU (smart key ECU assembly) connector.

*a	Front view of wire harness connector (to Certification ECU (Smart Key ECU Assembly))

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
J41-18 (E) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Condition	Specified Condition
J41-15 (CUTB) - Body ground	Always	11 to 14 V

REPAIR OR REPLACE HARNESS OR CONNECTOR

25.	CHECK ENTRY LOCK OPERATION

(a) Disconnect and reconnect the certification ECU (smart key ECU assembly) connectors.

(b) Check that the function operates normally.

Click here

Result	Proceed to
Entry function does not operate normally	A
Entry function operates normally	B

END (CONNECTOR WAS NOT CONNECTED SECURELY)

26.	REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

(a) Replace the certification ECU (smart key ECU assembly) with a new one and perform registration again.

HINT:

For replacement.
Click here
For registration.
Click here

27.	CHECK WIRELESS DOOR LOCK CONTROL SYSTEM

(a) Check that the function operates normally.

Click here

Result	Proceed to
Wireless door lock function operates normally	A
Wireless door lock function does not operate normally	B

END (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) WAS DEFECTIVE)

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

28.	CHECK WAVE ENVIRONMENT

(a) Bring the electrical key transmitter sub-assembly near the door control receiver and perform a wireless operation 2 or more times*.

*: When the wireless function is operated, channel 1 and 2 are used alternately. If the first wireless operation is performed successfully and the second wireless operation fails, wave interference may be occurring for either channel.

HINT:

When the electrical key transmitter sub-assembly is brought near the door control receiver, the possibility of wave interference decreases, and it can be determined if wave interference is causing the problem symptom.
If the inspection result is that the problem only occurs in certain locations or at certain times of day, the possibility of wave interference is high. Also, added vehicle components may cause wave interference. If installed, remove them and perform the operation check.
There may be wave interference if the vehicle is near broadcasting antennas, large video displays, wireless garage door opener systems, wireless security cameras, home security systems, etc. In this case, move the vehicle to a different location and check if there is any improvement.
If a tool for checking radio waves, such as a signal strength meter, is available, move around the area while observing both the LF band (used by the vehicle antenna to form the detection area) and RF band (used by the electrical key transmitter sub-assembly for transmission) to check for locations where there is wave interference.

Result	Proceed to
Wireless function does not operate normally	A
Wireless function operates normally 1 or more times.	B

AFFECTED BY WAVE INTERFERENCE

29.	CHECK ELECTRICAL KEY TRANSMITTER SUB-ASSEMBLY

(a) Check if there is another electrical key transmitter sub-assembly available that is already registered to the vehicle.

Result	Proceed to
Another registered electrical key transmitter sub-assembly is not available	A
Another registered electrical key transmitter sub-assembly is available	B

GO TO STEP 31

30.	ELECTRICAL KEY TRANSMITTER SUB-ASSEMBLY REGISTRATION (NEW ELECTRICAL KEY TRANSMITTER SUB-ASSEMBLY)

(a) Register a new electrical key transmitter sub-assembly.

Click here

31.	CHECK WAVE ENVIRONMENT

(a) Bring another registered electrical key transmitter sub-assembly near the door control receiver and perform a wireless operation 2 or more times*.

*: When the wireless function is operated, channel 1 and 2 are used alternately. If the first wireless operation is performed successfully and the second wireless operation fails, wave interference may be occurring for either channel.

HINT:

If the inspection result is that the problem only occurs in certain locations or at certain times of day, the possibility of wave interference is high. Also, added vehicle components may cause wave interference. If installed, remove them and perform the operation check.
There may be wave interference if the vehicle is near broadcasting antennas, large video displays, wireless garage door opener systems, wireless security cameras, home security systems, etc. In this case, move the vehicle to a different location and check if there is any improvement.
If a tool for checking radio waves, such as a signal strength meter, is available, move around the area while observing both the LF band (used by the vehicle antenna to form the detection area) and RF band (used by the electrical key transmitter sub-assembly for transmission) to check for locations where there is wave interference.

Result	Proceed to
Wireless function does not operate normally	A
Wireless function operates normally 1 or more times.	B

END (ELECTRICAL KEY TRANSMITTER SUB-ASSEMBLY WAS DEFECTIVE)

32.	CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - DOOR CONTROL RECEIVER)

(a) Disconnect the R23 door control receiver connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
R23-6 (CSEL) - R1-20 (CSEL)	Always	Below 1 Ω
R23-6 (CSEL) or R1-20 (CSEL) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

33.	CHECK ENTRY LOCK OPERATION

(a) Connect all connectors and check that the function operates normally.

Click here

Result	Proceed to
Entry function does not operate normally	A
Entry function operates normally	B

END (CONNECTOR WAS NOT CONNECTED SECURELY)

34.	CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
R23-6 (CSEL) - R23-12 (GND)	Procedure: Engine switch off All doors closed	Below 1 V → Pulse generation

*a	Component with harness connected (Door Control Receiver)

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

35.	CHECK DOOR CONTROL RECEIVER

(a) Enter key diagnostic mode and select the channel for which the wireless buzzer did not sound.

(b) Using an oscilloscope, check the waveform.

OK:

Tester Connection

Condition

Tool Setting

Specified Condition

R23-2 (DATA) - R23-12 (GND)

Procedure:

Engine switch off
All doors locked
Electrical key transmitter sub-assembly not inside vehicle
Electrical key transmitter sub-assembly brought outside detection area but kept inside wireless function operational area
Lock or unlock switch of electrical key transmitter sub-assembly not pressed → pressed

5 V/DIV., 500 ms/DIV.

Pulse generation

(See waveform 1)

HINT:

Inspection should be performed while the electrical key antenna check in key diagnostic mode is being performed on the failed channel (the channel in which the buzzer did not sound).

*a	Component with harness connected (Door Control Receiver)
*b	Waveform 1
*c	Before lock or unlock switch of electrical key transmitter sub-assembly pressed
*d	After lock or unlock switch of electrical key transmitter sub-assembly pressed

REPLACE DOOR CONTROL RECEIVER

36.	REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

(a) Replace the certification ECU (smart key ECU assembly) and perform registration again.

HINT:

For replacement.
Click here
For registration.
Click here

37.	CHECK WIRELESS DOOR LOCK CONTROL SYSTEM

(a) Check that the function operates normally.

Click here

Result	Proceed to
Wireless door lock function operates normally	A
Wireless door lock function does not operate normally	B

END (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) WAS DEFECTIVE)

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

Open in Outside Luggage Compartment Electrical Key Antenna Circuit (B27A8)

DESCRIPTION The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the electrical key antenna (outside luggage compartment). For the electrical key anten ...

All Door Entry Lock/Unlock Functions do not Operate, but Wireless Functions Operate

DESCRIPTION When the wireless operation can be used to lock and unlock the doors, communication between the door control receiver and certification ECU (smart key ECU assembly) is normal. If the entry ...

Other materials:

Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual > Rear Evaporator Temperature Sensor: Components
COMPONENTS ILLUSTRATION *1 COOLER UNIT CLAMP *2 HEATER RADIATOR UNIT SUB-ASSEMBLY *3 NO. 1 COOLING UNIT BRACKET *4 NO. 2 AIR CONDITIONING HARNESS ASSEMBLY *5 NO. 2 COOLING UNIT BRACKET *6 NO. 3 COOLING UNIT BRACKET *7 REAR NO. 1 COOLING UNIT DAMPER SERVO SUB-ASSEM ...

Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual > 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 ...

Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual: All Door Entry Lock/Unlock Functions and Wireless Functions do not Operate

Open in Outside Luggage Compartment Electrical Key Antenna Circuit (B27A8)

All Door Entry Lock/Unlock Functions do not Operate, but Wireless Functions Operate

Other materials:

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

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