Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Open in Bus 3 Main Bus Line

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 31 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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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.

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 ...

Check Bus 3 Lines for Short Circuit

DESCRIPTION There may be a short circuit between the bus 3 main lines and/or bus 3 branch lines when the resistance between terminals 6 (CA3H) and 21 (CA3L) of the network gateway ECU is below 54 Ω. ...

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