Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Certification ECU Communication Stop Mode

NOTICE:

• Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
• After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

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• Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

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• After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
• DTC check procedure: Turn the engine switch on (IG) and wait for at least 20 seconds.
• After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed.

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• Inspect the fuses for circuits related to this system before performing the following procedure.
• Before replacing the certification ECU (smart key ECU assembly), refer to the smart access system with push-button start (for Start Function) Precaution.

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HINT:

• Operating the engine switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.
• Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

Center Airbag Sensor Communication Stop Mode

DESCRIPTION Detection Item Symptom Trouble Area Center Airbag Sensor Communication Stop Mode Either condition is met: "Airbag" is not displayed on the CAN Bus Check screen of the Techs ...

Combination Meter ECU Communication Stop Mode

DESCRIPTION Detection Item Symptom Trouble Area Combination Meter ECU Communication Stop Mode Either condition is met: "Combination Meter" is not displayed on the CAN Bus Check screen ...

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Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Can Communication System: Check Bus 2 Line for Short to GND
DESCRIPTION There may be a short circuit between one of the CAN bus lines and GND when there is no resistance between terminal 18 (CA4H) of the network gateway ECU and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) of the network gateway ECU and terminal 4 (CG) of the DLC3. Symptom Trouble ...