LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Toyota >> 2017 >> 4Runner TRD Pro >> Repair and Diagnosis (Single Page) >> Body & Frame >> Door Locks >> Smart Key System (For Entry Function) - Symptom Tests >> SMART KEY SYSTEM (for Entry Function) >> Room Oscillator does not Recognize Key [08/2019 - 08/2021] >> Caution / Notice / Hint
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Caution / Notice / Hint

NOTE:
  • The smart key system (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 key system (for Entry Function) after confirming that the communication systems are functioning properly.

    Refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - 08/2021]

  • 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 Key. 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), refer to smart key system (for Entry Function) Precaution.

    Refer to PRECAUTION [08/2019 - 08/2021]

  • After repair, confirm that no DTCs are output by performing "DTC Output Confirmation Operation".
  • The indoor electrical key antenna assemblies have an antenna coil between each terminal.
  • The door control and tire pressure monitoring system receiver assembly is also related to interior verification.

HINT: 

RADIO WAVE INTERFERENCE

Parameter Name Cause of Problem and Countermeasure
Operating Engine Switch / Key RF Signal Interference When the engine switch was operated, the electrical key transmitter sub-assembly could not be confirmed due to wave interference. Therefore, the output frequency was switched to the other channel (changed from channel 1 to channel 2 or from channel 2 to channel 1).
If the cause of the malfunction has not been stored but any devices that can cause wave interference in the cabin have been removed and the room oscillator successfully recognizes the key, the possibility of wave interference is high.