Lexus NX: Open in One Side of Bus 3 Branch Line

Lexus NX Service Manual / Power Source & Network / Networking / Can Communication System / Open in One Side of Bus 3 Branch Line

DESCRIPTION

When the CAN bus main lines are normal (no open, short to ground, short to +B or short between lines) and there is an ECU or sensor on the "Communication Bus Check" screen that is indicated as not communicating or whose connection status on the "Communication Bus Check" screen changes intermittently, an open in one of the wires of a CAN bus branch line is suspected.

HINT:

If there is an ECU or sensor whose connection status changes intermittently while checking the "Communication Bus Check" screen, there may be an open circuit in one of the wires of a branch line of an ECU or sensor in the bus. If an open occurs in one of the wires of a CAN branch line, it may interfere with the communication of other ECUs or sensors resulting in an incorrect state being displayed.

Symptom	Trouble Area
1: w/ Telematics Transceiver 2: w/ Bus Buffer ECU
There is an ECU or sensor that is indicated as not communicating on the "Communication Bus Check" screen or whose connection status on the "Communication Bus Check" screen changes intermittently.	One side of CAN branch wire is open, or output signals are incomplete. DCM (telematics transceiver)1 Bus buffer ECU2 Radio receiver assembly

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

NOTICE:

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 power switch on (IG) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.
After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.
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Some parts must be initialized and set when replacing or removing and installing parts.
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The following malfunctions may occur if a radio receiver assembly from another vehicle is installed to this vehicle. Therefore, when replacing the radio receiver assembly, be sure to replace it with new one.
- Communication malfunction DTC is output
- Does not operate normally

PROCEDURE

1.	CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE

(a) Based on the vehicle equipment and specifications, confirm the systems that use CAN communication.

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(b) Connect the Techstream to the DLC3.

(d) Turn the Techstream on.

(e) Using the Techstream, perform "CAN Bus Check".

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CAN Bus Check

(f) Observe the screen for approximately 2 minutes to check for ECUs and sensors that are displayed as not communicating.

(g) Perform the inspection as specified in the Problem Symptoms Table for the ECUs or sensors that are not communicating.

GO TO CORRESPONDING COMMUNICATION STOP MODE

SEE MORE:

Ambient Temperature Sensor

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Bleeding

BLEEDING CAUTION / NOTICE / HINT CAUTION: The Techstream must be used for air bleeding. If not used, the air bleeding will be incomplete, which is hazardous and may lead to an accident. NOTICE: Perform air bleeding with park (P) selected and the parking brake applied. As brake fluid may overflo

Lexus NX: Open in One Side of Bus 3 Branch Line

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SEE MORE:

Ambient Temperature Sensor

Bleeding