Lexus ES: Open in One Side of Bus 4 Branch Line

Lexus ES (XZ10) Service Manual / Power Source & Network / Networking / Can Communication System (for Hv Model) / Open in One Side of Bus 4 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
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 line is open, or output signals are incomplete. Tire pressure warning ECU and receiver Occupant detection ECU Steering sensor Rack and pinion power steering gear assembly Hybrid vehicle control ECU Brake actuator assembly Brake booster with master cylinder assembly ECM

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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Before replacing the hybrid vehicle control ECU, refer to Registration.
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PROCEDURE

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

(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".

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:

Left Rear Wheel Speed Sensor Internal Electronic Failure (C050C49)

DESCRIPTION When the system is starting up and the skid control ECU (brake actuator assembly) detects a speed sensor circuit malfunction via the speed sensor circuit self-diagnosis function, this DTC is stored. DTC No. Detection Item DTC Detection Condition Trouble Area C050C49 Left R

Problem Symptoms Table

PROBLEM SYMPTOMS TABLE HINT: Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected

Lexus ES: Open in One Side of Bus 4 Branch Line

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Check Bus 4 Line for Short to GND

Check Bus 4 Line for Short to +B

Check Bus 4 Lines for Short Circuit

SEE MORE:

Left Rear Wheel Speed Sensor Internal Electronic Failure (C050C49)

Problem Symptoms Table