OPEN IN ONE SIDE OF CAN BRANCH LINE
CAN COMMUNICATION SYSTEM (for LHD) - Open in One Side of CAN Branch Line |
DESCRIPTION
If some ECUs and sensors are not displayed on the "Communication Bus Check" screen of the intelligent tester and some ECUs and sensors repeatedly appear and disappear from the screen when the CAN main bus lines are normal (there is no open, short, short to B+, or short to GND in the main bus lines), there may be an open circuit in either of the CAN branch lines.- HINT:
- If some ECUs and sensors repeatedly appear and disappear from the "Communication Bus Check" screen, communication between the normal ECUs (sensors) and intelligent tester may be affected by the incomplete signals that are output from the ECU that has an open circuit in either of its CAN branch lines. In this case, the CAN branch lines 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 lines).
| Symptom | Trouble Area |
| 2 or more ECUs and/or sensors do not appear on the intelligent tester "Communication Bus Check" screen. |
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WIRING DIAGRAM
INSPECTION PROCEDURE
| 1.OPEN IN ONE SIDE OF CAN BRANCH LINE |
Confirm the systems (ECUs and sensors), which use CAN communication, equipped on the vehicle. (Click here)
Using the intelligent tester, select and perform "Communication Bus Check". (Click here)
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.
Disconnect the branch line connectors, which are connected to the ECUs or sensors that are not displayed on the screen, from the CAN J/C.
Wiring color: CAN LH J/C A Side (with Earth Terminal) Code Color (CANH Side) Color (CANL Side) Steering angle sensor J1 P W ECM J2 B W Seat belt control ECU J3 V W Center airbag sensor J4 R W Wiring color: CAN LH J/C B Side (without Earth Terminal) Code Color (CANH Side) Color (CANL Side) Yaw rate sensor J5 P W Skid control ECU J6 R W CAN main bus line (bus line connecting CAN LH J/C and CAN RH J/C) J7 B W DLC3 J8 G W Distance control ECU J9 GR W 
Wiring color: CAN RH J/C A Side (with Earth Terminal) Code Color (CANH Side) Color (CANL Side) CAN main bus line (bus line connecting CAN RH J/C and CAN LH J/C) J81 B W Power steering ECU J82 P W Television camera ECU J94 L W Wiring color: CAN RH J/C B Side (without Earth Terminal) Code Color (CANH Side) Color (CANL Side) Gateway ECU J84 B W - HINT:
- Connecting locations of the connectors shown in the above tables are those of a vehicle whose connector locations have never been changed.
- If the connector locations differ from those shown in the above tables, identify each connector according to the color of the bus lines.
Check that the ECUs and sensors, which repeatedly appeared and disappeared from the "Communication Bus Check" screen, are constantly displayed.
Perform the communication stop mode check for the ECUs and sensors which correspond to the disconnected branch line connectors. (Click here).
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