Lexus IS250 IS220d GSE20 ALE20 - CAN COMMUNICATION
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. | One side of the CAN branch line is open Skid control ECU Steering angle sensor Yaw rate sensor ECM Gateway ECU Seat belt control ECU Distance control ECU Power steering ECU Television camera ECU Center airbag sensor |
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.
Using the intelligent tester, select and perform "Communication Bus Check".
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.
| 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 |
| 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 |
| 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 |
| CAN RH J/C B Side (without Earth Terminal) | Code | Color (CANH Side) | Color (CANL Side) |
| Gateway ECU | J84 | B | W |
- HINT:
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. .
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