Toyota Tundra Service Manual: Open in One Side of Bus 4 Branch Line

Toyota Tundra Service Manual / Power Source, Network / Can Communication / Can Communication System / 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

*1: for 4WD

*2: w/ Trailer Brake Control System

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.

4 wheel drive control ECU (4WD control ECU)*1
Tire pressure warning ECU and receiver
Brake control with bracket relay*2
Spiral with sensor cable sub-assembly (steering angle sensor)
Brake actuator assembly (skid control ECU)

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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Some parts must be initialized and set when replacing or removing and installing parts.
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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 ignition switch to ON 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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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".

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(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

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Toyota Tundra Service Manual: Open in One Side of Bus 4 Branch Line

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