Lexus NX: Front Passenger Side Door Entry Lock and Unlock Functions do not Operate

DESCRIPTION

If the entry lock and unlock functions do not operate for the front passenger door only, the request code may not be being transmitted from the front passenger door or the front door outside handle assembly (for front passenger door) (touch sensor) may be malfunctioning. If the entry functions for other doors operate properly, communication between the electrical key transmitter sub-assembly and door control receiver is normal. In this case, there may be a problem with request code transmission (communication between the certification ECU (smart key ECU assembly) and front door outside handle assembly (for front passenger door) (electrical key antenna)), or there may be wave interference.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

(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.

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OK:

Door locks operate normally.

NG

GO TO POWER DOOR LOCK CONTROL SYSTEM

OK

(a) Check for DTCs.

B

GO TO DIAGNOSTIC TROUBLE CODE CHART

A

(a) Bring the electrical key transmitter sub-assembly approximately 0.3 m (0.984 ft.) from the front door outside handle assembly (for front passenger door) and perform an entry function check. Click here Communication may not be possible if the electrical key transmitter sub-assembly is within 0.2 m (0.656 ft.) of the front door outside handle assembly (for front passenger door). When the electrical key transmitter sub-assembly is brought near the front door outside handle assembly (for front passenger door), 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. When checking the operation of the entry lock function several times, it can be operated up to 2 times consecutively. To operate the function 3 times or more consecutively, the doors need to be unlocked once. However, this is only for the entry lock function, other door lock operations, such as a wireless door lock operation can be performed consecutively.

*a Approximately 0.3 m (0.984 ft.)

B

AFFECTED BY WAVE INTERFERENCE

A

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

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

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

HINT:

When checking the operation of the entry lock function several times, it can be operated up to 2 times consecutively. To operate the function 3 times or more consecutively, the doors need to be unlocked once. However, this is only for the entry lock function, other door lock operations, such as a wireless door lock operation can be performed consecutively.

OK:

The Techstream display changes correctly in response to the operation of the front door outside handle assembly (for front passenger door).

NG

GO TO STEP 6

OK

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

(b) Select either channel 1 or channel 2 and perform key diagnostic mode inspection for each channel.

(1) 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 inspect key diagnostic mode 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.)

B

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

A

(a) Disconnect the I53 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the L4 front door outside handle assembly (for front passenger door) connector.

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

Standard Resistance:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Connect the I53 certification ECU (smart key ECU assembly) connector.

*a Front view of wire harness connector (to Front Door Outside Handle Assembly (for Front Passenger Door)) *b Waveform 1

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

OK:

*: For details about the entry function detection area, refer to Operation Check.

Click here

NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

OK

(a) Connect all connectors and check that the entry lock and unlock functions operate.

Click here

B

END (CONNECTOR WAS NOT CONNECTED SECURELY)

A

(a) Replace the front door outside handle assembly (for front passenger door) with a new one or the front door outside handle assembly (for driver door) if it is functioning properly.

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NEXT

(a) Check that the entry lock and unlock functions operate.

Click here

A

END (FRONT DOOR OUTSIDE HANDLE ASSEMBLY (FOR FRONT PASSENGER DOOR) WAS DEFECTIVE)

B

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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