Lexus ES: Open in Bus 2 Main Bus Line
DESCRIPTION
There may be an open circuit in one of the CAN main bus lines when the resistance between terminals 18 (CA4H) and 17 (CA4L) of the central gateway ECU (network gateway ECU) is 70 Ω or higher.
| Symptom | Trouble Area |
|---|---|
| Resistance between terminals 18 (CA4H) and 17 (CA4L) of the central gateway ECU (network gateway ECU) is 70 Ω or higher. |
|
This malfunction is not related to the lines of a CAN branch or to ECUs or sensors connected to a CAN branch.
WIRING DIAGRAM
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CAUTION / NOTICE / HINT
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
NOTICE:
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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 engine 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.
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After turning the engine 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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After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
DTC check procedure: Turn the engine switch on (IG) 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.
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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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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 CAN MAIN BUS LINES (NO. 2 JUNCTION CONNECTOR) |
(a) Disconnect the cable from the negative (-) battery terminal.
(b) Disconnect the A71 No. 2 junction connector.
(c) Measure the resistance according to the value(s) in the table below.
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| *a | Front view of wire harness connector (to No. 2 Junction Connector) | *b | to No. 4 CAN Junction Connector |
| *c | to ECM | - | - |
Standard Resistance:
| Tester Connection | Condition | Specified Condition | Connected to |
|---|---|---|---|
| A71-8 (CANH) - A71-19 (CANL) | Cable disconnected from negative (-) battery terminal | 108 to 132 Ω | No. 4 CAN junction connector |
| A71-11 (CANH) - A71-22 (CANL) | Cable disconnected from negative (-) battery terminal | 108 to 132 Ω | ECM |
| Result | Proceed to |
|---|---|
| OK | A |
| NG (Line to ECM) | B |
| NG (Line to No. 4 CAN junction connector) | C |
| A | .gif) | REPLACE NO. 2 JUNCTION CONNECTOR |
| C | | GO TO STEP 3 |
|
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| 2. | CHECK FOR OPEN IN CAN MAIN BUS LINES (ECM) |
(a) Reconnect the A71 No. 2 junction connector.
(b) Disconnect the A25 ECM connector.
| (c) Measure the resistance according to the value(s) in the table below. Standard Resistance:
|
|
| OK | | REPLACE ECM |
| NG | | REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (ECM - NO. 2 JUNCTION CONNECTOR) |
| 3. | CHECK FOR OPEN IN CAN MAIN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR - NO. 2 JUNCTION CONNECTOR) |
(a) Reconnect the A71 No. 2 junction connector.
(b) Disconnect the G99 No. 4 CAN junction connector.
(c) Measure the resistance according to the value(s) in the table below.
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| *a | Front view of wire harness connector (to No. 4 CAN Junction Connector) | *b | to No. 2 Junction Connector |
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| G99-11 (CANH) - G99-22 (CANL) | Cable disconnected from negative (-) battery terminal | 108 to 132 Ω |
| NG | | REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 2 JUNCTION CONNECTOR) |
|
| 4. | CHECK FOR OPEN IN CAN MAIN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR) |
(a) Reconnect the G99 No. 4 CAN junction connector.
(b) Disconnect the G98 No. 4 CAN junction connector.
(c) Measure the resistance according to the value(s) in the table below.
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| *a | Front view of wire harness connector (to No. 4 CAN Junction Connector) | *b | to Central Gateway ECU (Network Gateway ECU) |
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| G98-1 (CANH) - G98-12 (CANL) | Cable disconnected from negative (-) battery terminal | 108 to 132 Ω |
| OK | | REPLACE NO. 4 CAN JUNCTION CONNECTOR |
|
| 5. | CHECK FOR OPEN IN CAN MAIN BUS LINES (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) |
(a) Reconnect the G98 No. 4 CAN junction connector.
(b) Disconnect the G66 central gateway ECU (network gateway ECU) connector.
| (c) Measure the resistance according to the value(s) in the table below. Standard Resistance:
|
|
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| OK | | REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) |
| NG | | REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - NO. 4 CAN JUNCTION CONNECTOR) |
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