Toyota Venza: Open in One Side of CAN Branch Line

Toyota Venza Service Manual / Networking / Can Communication System / Open in One Side of CAN Branch Line

DESCRIPTION

If some ECUs and sensors are not displayed on the "CAN Bus Check" screen of the Techstream and some ECUs and sensors repeatedly appear and disappear from the screen when the CAN main bus wires are normal (there is no open, short, short to B+ or short to GND in the main bus wires), there may be an open circuit in either of the CAN branch wires.

HINT:

If some ECUs and sensors repeatedly appear and disappear from the "CAN Bus Check" screen, communication between the normal ECUs (sensors) and the Techstream may be affected by the incomplete signals that are output from the ECU that has an open circuit in either of its CAN branch wires. In this case, the CAN branch wires for the ECUs and sensors that repeatedly appear and disappear from the screen are normal and the ECU that is not displayed on the screen may be the main cause of the problem (this ECU may have an open circuit in either of its CAN branch wires).

Symptom	Trouble Area
2 or more ECUs and/or sensors do not appear on the Techstream "Communication Bus Check" screen.	One side of CAN branch wire is open, or output signals are incomplete. Combination meter ECM Power steering ECU Center airbag sensor assembly Air conditioning amplifier3 Skid control ECU (Brake actuator) Steering angle sensor Yaw rate sensor Main body ECU (Driver side junction block) 4WD control ECU1 Certification ECU2 Power management control ECU2 Navigation receiver assembly4 Radio and display receiver assembly5

Symptom

Trouble Area

2 or more ECUs and/or sensors do not appear on the Techstream "Communication Bus Check" screen.

One side of CAN branch wire is open, or output signals are incomplete.

Combination meter
ECM
Power steering ECU
Center airbag sensor assembly
Air conditioning amplifier*3
Skid control ECU (Brake actuator)
Steering angle sensor
Yaw rate sensor
Main body ECU (Driver side junction block)
4WD control ECU*1
Certification ECU*2
Power management control ECU*2
Navigation receiver assembly*4
Radio and display receiver assembly*5

*1: for AWD

*2: w/ Smart key system

*3: w/o Smart key system

*4: for Navigation system

*5: for Audio and visual system

CAUTION / NOTICE / HINT

HINT:

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 will help determine the cause of the malfunction.

PROCEDURE

1.	CHECK FOR OPEN IN ONE SIDE OF CAN NO. 1 BUS BRANCH WIRE

(a) Confirm the systems (ECUs and sensors), which use CAN communication, equipped on the vehicle (See page ).

(b) Using the Techstream, select and perform "CAN Bus Check" (See page ).

(c) Observe the screen for approximately 1 minute to check the ECUs and sensors that are not displayed on the screen and also those that repeatedly appear and disappear from the screen.

(d) Check that the ECUs and sensors, which are connected to the ECUs or sensors that are not displayed on the screen.

(e) Check that the ECUs and sensors, which repeatedly appeared and disappeared from the "CAN Bus Check" screen, are constantly displayed.

GO TO CORRESPONDING COMMUNICATION STOP MODE

Check CAN Bus Line for Short to GND

DESCRIPTION There may be a short circuit between the CAN bus main wire and GND when there is no resistance between terminals 6 (CANH) and 4 (CG) or 14 (CANL) and 4 (CG) of the DLC3. S ...

Lin Communication System

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