Room Oscillator Does Not Recognize Key

THEFT DETERRENT / KEYLESS ENTRY: SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Entry Function): Room Oscillator does not Recognize Key
- Room Oscillator does not Recognize Key

DESCRIPTION

If code verification cannot be performed in the vehicle interior, there may be problems with the communication between the vehicle (indoor electrical key antenna assembly [front floor], [rear floor] or [inside luggage]) and key, or the certification ECU (smart key ECU assembly) may be malfunctioning. When the key is brought into the vehicle, verification of the key ID code transmitted from the key and the key ID code stored in the certification ECU (smart key ECU assembly) is performed. If verification cannot be performed or the codes do not match, the power switch cannot be turned on (IG) and the hybrid control system cannot be started.

When a door is unlocked and the key is brought into the vehicle, the certification ECU (smart key ECU assembly) activates the indoor electrical key antenna assembly which transmits electric waves to detect the key. If the key recognizes that it is in the detection area, it responds with the key ID code. This information is received by the indoor electrical key antenna and then sent to the certification ECU (smart key ECU assembly).

WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
* The smart access system with push-button start (for Entry Function) uses a multiplex communication system (LIN communication system) and the CAN communication system. Inspect the communication function by following How to Proceed with Troubleshooting 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.
* When using the Techstream with the power switch off to troubleshoot:
Connect the Techstream to the vehicle and turn a courtesy light switch on and off at 1.5-second intervals until communication between the Techstream and vehicle begins.
* Before replacing the certification ECU (smart key ECU assembly), refer to the smart access system with push-button start (for Entry Function) Smart Access System With Push-Button Start (For Entry Function).
* After repair, confirm DTC not reoccur with performing the "DTC Output Confirmation Operation".
* Indoor electrical key antenna assembly have an antenna coil between each two CLG terminals.

PROCEDURE

1. CHECK SMART ACCESS SYSTEM WITH PUSH-BUTTON START (FOR ENTRY FUNCTION)

(a) Check that the entry lock and unlock functions operate for each door Operation Check.

NG -- GO TO PROBLEM SYMPTOMS TABLE Problem Symptoms Table
OK -- Continue to next step.

2. CHECK SMART ACCESS SYSTEM WITH PUSH-BUTTON START (FOR START FUNCTION)

(a) Remove the battery of the electrical key transmitter Operation Check.





(b) With the brake pedal depressed, touch the LEXUS mark of the key to the power switch.

(c) When operating the power switch, check whether the hybrid control system starts.

HINT
* When the key cannot be verified even though it is inside the detection area, the hybrid control system start check can be performed by removing the battery from the key and holding the key against the power switch.
* If the hybrid control system cannot be started when performing this inspection, the certification ECU (smart key ECU assembly) or ID code box may be malfunctioning.

OK:

Hybrid control system starts.

Text in Illustration





NG -- GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (FOR START FUNCTION) How To Proceed With Troubleshooting
OK -- Continue to next step.

3. CHECK WAVE ENVIRONMENT

(a) Install the battery to the electrical key transmitter Installation.

(b) Bring the electrical key transmitter near the door control receiver and perform a smart access system with push-button start check Operation Check.

HINT
As the effect of electric wave interference decreases by moving the key close to the door control receiver, it may be possible to check whether electric wave interference is the cause of the problem.

Result





HINT
* If the problem only occurs in specific places or at specific times, electric wave interference may be the cause of the problem. Also, the vehicle may be have the effects of electric wave interference with the parts installed by the dealer. As a result, when parts have been installed by the dealer, it may be necessary to remove those parts before inspecting the vehicle.
* There may be electric 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 electric 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 key detection area) and RF band (used by the key for transmission) to check for locations where there is electric wave interference.

B -- AFFECTED BY WAVE INTERFERENCE
A -- Continue to next step.

4. CHECK ELECTRICAL KEY ANTENNAS IN KEY DIAGNOSTIC MODE

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

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





Text in Illustration





When the electrical key transmitter is at the inspection point, check that the wireless door lock buzzer sounds.

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





Text in Illustration





When the electrical key transmitter is at the inspection point, check that the wireless door lock buzzer sounds.

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





Text in Illustration





When the electrical key transmitter is at the inspection point, check that the wireless door lock buzzer sounds.

HINT
* If the buzzer sounds, it can be determined that the vehicle interior transmitters are operating normally.
* It is possible to check which indoor electrical key antenna assembly (front floor, rear floor or inside luggage) is operating by the sounding of the buzzer.
* If the buzzer does not sound for any indoor electrical key antenna assemblies, the certification ECU (smart key ECU assembly) circuit may have a malfunction.

OK:

Wireless door lock buzzer sounds.

Result





B -- CHECK HARNESS AND CONNECTOR (NO. 2 INDOOR ELECTRICAL KEY ANTENNA - CERTIFICATION ECU)

C -- CHECK HARNESS AND CONNECTOR (NO. 3 INDOOR ELECTRICAL KEY ANTENNA - CERTIFICATION ECU)

D -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Removal
A -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (NO. 1 INDOOR ELECTRICAL KEY ANTENNA - CERTIFICATION ECU)

(a) Disconnect the H74 No. 1 indoor electrical key antenna assembly (front floor) connector.

(b) Disconnect the H1 certification ECU (smart key ECU assembly) connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

6. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO NO. 1 INDOOR ELECTRICAL KEY ANTENNA [FRONT FLOOR])

(a) Disconnect the H74 No. 1 indoor electrical key antenna assembly (front floor) connector.





(b) Connect the H1 certification ECU (smart key ECU assembly) connector.

(c) Using an oscilloscope, check the waveform.

OK:





Text in Illustration





NG -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Removal
OK -- Continue to next step.

7. REPLACE NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (FRONT FLOOR)

(a) Temporarily replace the No. 1 indoor electrical key antenna assembly (front floor) with a new or normally functioning one Removal.

NEXT -- Continue to next step.

8. CHECK ELECTRICAL KEY ANTENNA IN KEY DIAGNOSTIC MODE

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

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





When the electrical key transmitter is at the inspection point, check that the wireless door lock buzzer sounds.

OK:

Wireless door lock buzzer sounds.

Text in Illustration





NG -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Removal

OK -- END (NO. 1 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY IS DEFECTIVE)

9. CHECK HARNESS AND CONNECTOR (NO. 2 INDOOR ELECTRICAL KEY ANTENNA - CERTIFICATION ECU)

(a) Disconnect the P8 No. 2 indoor electrical key antenna assembly (rear floor) connector.

(b) Disconnect the H1 certification ECU (smart key ECU assembly) connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

10. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO NO. 2 INDOOR ELECTRICAL KEY ANTENNA [REAR FLOOR])

(a) Disconnect the P8 No. 2 indoor electrical key antenna assembly (rear floor) connector.





(b) Connect the H1 certification ECU (smart key ECU assembly) connector.

(c) Using an oscilloscope, check the waveform.

OK:





Text in Illustration





NG -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Removal
OK -- Continue to next step.

11. REPLACE NO. 2 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (REAR FLOOR)

(a) Temporarily replace the No. 2 indoor electrical key antenna assembly (rear floor) with a new or normally functioning one Removal.

NEXT -- Continue to next step.

12. CHECK ELECTRICAL KEY ANTENNA IN KEY DIAGNOSTIC MODE

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

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





When the electrical key transmitter is at the inspection point, check that the wireless door lock buzzer sounds.

OK:

Wireless door lock buzzer sounds.

Text in Illustration





NG -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Removal

OK -- END (NO. 2 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY WAS DEFECTIVE)

13. CHECK HARNESS AND CONNECTOR (NO. 3 INDOOR ELECTRICAL KEY ANTENNA - CERTIFICATION ECU)

(a) Disconnect the Q12 No. 3 indoor electrical key antenna assembly (inside luggage) connector.

(b) Disconnect the H1 certification ECU (smart key ECU assembly) connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

14. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (OUTPUT TO INDOOR NO. 3 ELECTRICAL KEY ANTENNA)

(a) Disconnect the Q12 No. 3 indoor electrical key antenna assembly (inside luggage) connector.





(b) Connect the H1 certification ECU (smart key ECU assembly) connector.

(c) Using an oscilloscope, check the waveform.

OK:





Text in Illustration





NG -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Removal
OK -- Continue to next step.

15. REPLACE NO. 3 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY (INSIDE LUGGAGE)

(a) Temporarily replace the No. 3 indoor electrical key antenna assembly (inside luggage) with a new or normally functioning one Removal.

NEXT -- Continue to next step.

16. CHECK ELECTRICAL KEY ANTENNA IN KEY DIAGNOSTIC MODE

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

(1) Check the No. 3 indoor electrical key antenna assembly (inside luggage).





When the electrical key transmitter is at the inspection point, check that the wireless door lock buzzer sounds.

OK:

Wireless door lock buzzer sounds.

Text in Illustration





NG -- REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) Removal

OK -- END (NO. 3 INDOOR ELECTRICAL KEY ANTENNA ASSEMBLY WAS DEFECTIVE)