Lexus ES: Check Bus 5 Lines for Short Circuit
DESCRIPTION
There may be a short circuit between the CAN main bus lines and/or CAN branch lines when the resistance between terminals 15 (CA5H) and 16 (CA5L) of the central gateway ECU (network gateway ECU) is below 54 Ω.
| Symptom | Trouble Area |
|---|---|
| Resistance between terminals 15 (CA5H) and 16 (CA5L) of the central gateway ECU (network gateway ECU) is below 54 Ω. |
|
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.
Click here
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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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Before replacing the main body ECU (multiplex network body ECU) or certification ECU (smart key ECU assembly), 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 SHORT IN CAN BUS LINES (NO. 1 JUNCTION CONNECTOR) |
(a) Disconnect the cable from the negative (-) battery terminal.
(b) Disconnect the N97 No. 1 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. 1 Junction Connector) | *b | to Central Gateway ECU (Network Gateway ECU) |
| *c | to Headlight ECU Sub-assembly RH | *d | to Outer Mirror Control ECU Assembly RH (w/ Seat Position Memory System) |
| *e | to No. 8 CAN Junction Connector | - | - |
Standard Resistance:
| Tester Connection | Condition | Specified Condition | Connected to |
|---|---|---|---|
| N97-8 (CANH) - N97-19 (CANL) | Cable disconnected from negative (-) battery terminal | 108 to 132 Ω | Central gateway ECU (network gateway ECU) |
| N97-9 (CANH) - N97-20 (CANL) | Cable disconnected from negative (-) battery terminal | 200 Ω or higher | Headlight ECU sub-assembly RH |
| N97-10 (CANH) - N97-21 (CANL) | Cable disconnected from negative (-) battery terminal | 200 Ω or higher | Outer mirror control ECU assembly RH* |
| N97-11 (CANH) - N97-22 (CANL) | Cable disconnected from negative (-) battery terminal | 108 to 132 Ω | No. 8 CAN junction connector |
- *: w/ Seat Position Memory System
| Result | Proceed to |
|---|---|
| OK | A |
| NG (Line to central gateway ECU (network gateway ECU)) | B |
| NG (Line to No. 8 CAN junction connector) | C |
| NG (Line to ECU or sensor) | D |
| A | .gif) | REPLACE NO. 1 JUNCTION CONNECTOR |
| C | | GO TO STEP 3 |
| D | | GO TO STEP 6 |
|
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| 2. | CHECK FOR SHORT IN CAN BUS LINES (NO. 1 JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) |
(a) Disconnect the G66 central gateway ECU (network gateway ECU) connector.
(b) 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. 1 Junction Connector) | *b | to Central Gateway ECU (Network Gateway ECU) |
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| N97-8 (CANH) - N97-19 (CANL) | Cable disconnected from negative (-) battery terminal | 1 MΩ or higher |
| OK | | REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) |
| NG | | REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 1 JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) |
| 3. | CHECK FOR SHORT IN CAN BUS LINES (NO. 8 CAN JUNCTION CONNECTOR) |
(a) Reconnect the N97 No. 1 junction connector.
(b) Disconnect the N101 No. 8 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. 8 CAN Junction Connector) | *b | to Outer Mirror Control ECU Assembly LH (w/ Seat Position Memory System) |
| *c | to Luggage Closer Motor Assembly (w/ Power Trunk Lid System) | *d | to No. 5 CAN Junction Connector |
| *e | to No. 1 Junction Connector | *f | to Position Control ECU Assembly LH (w/ Seat Position Memory System) |
Standard Resistance:
| Tester Connection | Condition | Specified Condition | Connected to |
|---|---|---|---|
| N101-1 (CANH) - N101-7 (CANL) | Cable disconnected from negative (-) battery terminal | 200 Ω or higher | Outer mirror control ECU assembly LH*1 |
| N101-2 (CANH) - N101-8 (CANL) | Cable disconnected from negative (-) battery terminal | 200 Ω or higher | Luggage closer motor assembly*2 |
| N101-3 (CANH) - N101-9 (CANL) | Cable disconnected from negative (-) battery terminal | 108 to 132 Ω | No. 5 CAN junction connector |
| N101-4 (CANH) - N101-10 (CANL) | Cable disconnected from negative (-) battery terminal | 108 to 132 Ω | No. 1 junction connector |
| N101-5 (CANH) - N101-11 (CANL) | Cable disconnected from negative (-) battery terminal | 200 Ω or higher | Position control ECU assembly LH*1 |
- *1: w/ Seat Position Memory System
- *2: w/ Power Trunk Lid System
| Result | Proceed to |
|---|---|
| OK | A |
| NG (Line to No. 1 junction connector) | B |
| NG (Line to No. 5 CAN junction connector) | C |
| NG (Line to ECU or sensor) | D |
| A | | REPLACE NO. 8 CAN JUNCTION CONNECTOR |
| B | | REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 8 CAN JUNCTION CONNECTOR - NO. 1 JUNCTION CONNECTOR) |
| D | | GO TO STEP 6 |
|
| 4. | CHECK FOR SHORT IN CAN BUS LINES (NO. 5 CAN JUNCTION CONNECTOR) |
(a) Reconnect the N101 No. 8 CAN junction connector.
(b) Disconnect the G97 No. 5 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. 5 CAN Junction Connector) | *b | to Air Conditioning Amplifier Assembly |
| *c | to Certification ECU (Smart Key ECU Assembly) | *d | to Headlight ECU Sub-assembly LH |
| *e | to Main Body ECU (Multiplex Network Body ECU) | *f | to No. 8 CAN Junction Connector |
| *g | to Combination Meter Assembly | *h | to Meter Mirror Sub-assembly (w/ Headup Display System) |
| *i | to Multiplex Tilt and Telescopic ECU (w/ Power Tilt and Power Telescopic System) | - | - |
Standard Resistance:
| Tester Connection | Condition | Specified Condition | Connected to |
|---|---|---|---|
| G97-3 (CANH) - G97-14 (CANL) | Cable disconnected from negative (-) battery terminal | 200 Ω or higher | Air conditioning amplifier assembly |
| G97-4 (CANH) - G97-15 (CANL) | Cable disconnected from negative (-) battery terminal | 200 Ω or higher | Certification ECU (smart key ECU assembly) |
| G97-5 (CANH) - G97-16 (CANL) | Cable disconnected from negative (-) battery terminal | 200 Ω or higher | Headlight ECU sub-assembly LH |
| G97-6 (CANH) - G97-17 (CANL) | Cable disconnected from negative (-) battery terminal | 200 Ω or higher | Main body ECU (multiplex network body ECU) |
| G97-7 (CANH) - G97-18 (CANL) | Cable disconnected from negative (-) battery terminal | 108 to 132 Ω | No. 8 CAN junction connector |
| G97-8 (CANH) - G97-19 (CANL) | Cable disconnected from negative (-) battery terminal | 108 to 132 Ω | Combination meter assembly |
| G97-9 (CANH) - G97-20 (CANL) | Cable disconnected from negative (-) battery terminal | 200 Ω or higher | Meter mirror sub-assembly*1 |
| G97-10 (CANH) - G97-21 (CANL) | Cable disconnected from negative (-) battery terminal | 200 Ω or higher | Multiplex tilt and telescopic ECU*2 |
- *1: w/ Headup Display System
- *2: w/ Power Tilt and Power Telescopic System
| Result | Proceed to |
|---|---|
| OK | A |
| NG (Line to No. 8 CAN junction connector) | B |
| NG (Line to combination meter assembly) | C |
| NG (Line to ECU or sensor) | D |
| A | | REPLACE NO. 5 CAN JUNCTION CONNECTOR |
| B | | REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 5 CAN JUNCTION CONNECTOR - NO. 8 CAN JUNCTION CONNECTOR) |
| D | | GO TO STEP 6 |
|
| 5. | CHECK FOR SHORT IN CAN BUS LINES (NO. 5 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY) |
(a) Disconnect the G17 combination meter assembly connector.
(b) 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. 5 CAN Junction Connector) | *b | to Combination Meter Assembly |
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| G97-8 (CANH) - G97-19 (CANL) | Cable disconnected from negative (-) battery terminal | 1 MΩ or higher |
| OK | | REPLACE COMBINATION METER ASSEMBLY |
| NG | | REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 5 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY) |
| 6. | CHECK FOR SHORT IN CAN BUS LINES (ECU OR SENSOR) |
(a) Reconnect all wire harness connectors.
(b) Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the short circuited branch line is connected.
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| (c) Measure the resistance according to the value(s) in the table below. Standard Resistance:
HINT:
|
|
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| OK | | REPLACE ECU OR SENSOR |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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