Toyota Tacoma 2015-2018 Service Manual: Open in One Side of Bus 2 Branch Line

Toyota Tacoma 2015-2018 Service Manual / Can Communication / Can Communication System / Open in One Side of Bus 2 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.

Detection Item	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. Main body ECU (multiplex network body ECU) Air conditioning amplifier assembly Airbag sensor assembly Spiral cable with sensor sub-assembly (Steering sensor) Certification ECU (smart key ECU assembly)1 4 wheel drive control ECU2 Door control and tire pressure monitoring system receiver assembly3 Brake booster assembly (skid control ECU)4 Brake actuator assembly (skid control ECU)*5

Detection Item

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.

Main body ECU (multiplex network body ECU)
Air conditioning amplifier assembly
Airbag sensor assembly
Spiral cable with sensor sub-assembly (Steering sensor)
Certification ECU (smart key ECU assembly)*1
4 wheel drive control ECU*2
Door control and tire pressure monitoring system receiver assembly*3
Brake booster assembly (skid control ECU)*4
Brake actuator assembly (skid control ECU)*5

*1: w/ Smart Key System
*2: for 4WD
*3: w/ Tire Pressure Warning System and Tire Inflation Pressure Display Function
*4: for Hydraulic Brake Booster
*5: for Vacuum Brake Booster

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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Before measuring the resistance of the CAN bus, turn the ignition 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 ignition 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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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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If the main body ECU (multiplex network body ECU) or certification ECU (smart key ECU assembly) is replaced, refer to Registration.
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HINT:

Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.
When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE

1.	CHECK FOR OPEN IN ONE SIDE OF BUS 2 CAN BRANCH LINE

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

Click here (b) Connect the Techstream to the DLC3.

(b) Connect the Techstream to the DLC3.

(d) Turn the Techstream on.

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

Click here (f) Observe the screen for approximately 2 minutes to check for ECUs and sensors

(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

Open in Bus 3 Main Bus Line

DESCRIPTION There may be an open circuit in one of the CAN main bus lines when the resistance between terminals 6 (CA3H) and 21 (CA3L) of the central gateway ECU (network gateway ECU) is 70 Ω or ...

Check Bus 3 Line for Short to +B

DESCRIPTION There may be a short circuit between one of the CAN bus lines and +B when no resistance exists between terminal 6 (CA3H) of the central gateway ECU (network gateway ECU) and terminal ...

Other materials:

Diagnosis System
DIAGNOSIS SYSTEM 1. DESCRIPTION (a) Blind spot monitor data and Diagnostic Trouble Codes (DTCs) can be read from the Data Link Connector 3 (DLC3) of the vehicle. When the system seems to be malfunctioning, use the Techstream to check for malfunctions and to repair it. 2. CHECK DLC3 (a) Check ...

Registration
REGISTRATION PROCEDURE 1. BEFORE REGISTRATION NOTICE: The transmitter ID is written on the tire pressure warning valve and transmitter. It is not possible to read the transmitter ID after installing the tire onto the wheel. Therefore, make a note of the transmitter ID before installing the t ...

Air Inlet Control Servo Motor
Inspection INSPECTION PROCEDURE 1. INSPECT AIR INLET CONTROL SERVO MOTOR (a) Inspect the servo motor operation. (1) Connect the positive (+) lead from the battery to terminal 1 (FRS) and negative (-) lead to terminals 2 (REC), then check that the shaft rotates clockwise s ...