DESCRIPTION
There may be a short circuit between one of the CAN bus lines and GND when there is no resistance between terminal 15 (CA5H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.
Symptom | Trouble Area |
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There is no resistance between terminal 15 (CA5H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3. |
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WIRING DIAGRAM
CAUTION / NOTICE / HINT
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
Note
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.
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.
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.
Some parts must be initialized and set when replacing or removing and installing parts.
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.
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.
Tech Tips
Operating the engine switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.
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 may help determine the cause of the malfunction.
PROCEDURE
CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 3 CAN JUNCTION CONNECTOR)
Disconnect the cable from the negative (-) battery terminal.
Disconnect the No. 3 CAN junction connector.
*a | Front view of wire harness connector (to No. 3 CAN Junction Connector) |
*b | to Central Gateway ECU (Network Gateway ECU) |
*c | to Millimeter Wave Radar Sensor Assembly (w/ Pre-collision System) | *d | to Clearance Warning ECU Assembly (w/ LEXUS Parking Assist-sensor System) |
*e | to Driving Support ECU Assembly (w/ Pre-collision System) | *f | to Forward Recognition Camera (w/ Pre-collision System) |
*g | to No. 6 CAN Junction Connector | *h | Front view of DLC3 |
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||||||||||||||||||||||||||||||
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*2: w/ LEXUS Parking Assist-sensor System |
Result | ||||||||||
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A |
REPLACE NO. 3 CAN JUNCTION CONNECTOR |
C |
CONNECT CONNECTOR Click here |
D |
GO TO STEP 8 Click here |
B |
CONNECT CONNECTOR
Reconnect the I95 No. 3 CAN junction connector.
Result | ||
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NEXT |
CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 3 CAN JUNCTION CONNECTOR)
Disconnect the central gateway ECU (network gateway ECU) connector.
*a | Front view of wire harness connector (to Central Gateway ECU [Network Gateway ECU]) |
*b | Front view of DLC3 |
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||
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Result | |||
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OK |
REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) for LHD: Click here |
NG |
REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 3 CAN JUNCTION CONNECTOR) |
CONNECT CONNECTOR
Reconnect the I95 No. 3 CAN junction connector.
Result | ||
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|
NEXT |
CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 6 CAN JUNCTION CONNECTOR)
Disconnect the No. 6 CAN junction connector.
*a | Front view of wire harness connector (to No. 6 CAN Junction Connector) |
*b | to Parking Assist ECU (w/ Panoramic View Monitor System) |
*c | to Blind Spot Monitor Sensor LH (w/ Blind Spot Monitor System) | *d | to Central Gateway ECU (Network Gateway ECU) |
*e | to No. 3 CAN Junction Connector | *f | to Absorber Control ECU (w/ Adaptive Variable Suspension System) |
*g | to Rear Television Camera Assembly (w/ Parking Assist Monitor System) | *h | Front view of DLC3 |
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||||||||||||||||||||||||||||||
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*2: w/ Blind Spot Monitor System *3: w/ Adaptive Variable Suspension System *4: w/ Parking Assist Monitor System |
Result | ||||||||||
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A |
REPLACE NO. 6 CAN JUNCTION CONNECTOR |
C |
REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 2 CAN JUNCTION CONNECTOR - NO. 1 CAN JUNCTION CONNECTOR) |
D |
CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR) Click here |
B |
CONNECT CONNECTOR
Reconnect the Q32 No. 6 CAN junction connector.
Result | ||
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|
NEXT |
CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 6 CAN JUNCTION CONNECTOR)
Disconnect the central gateway ECU (network gateway ECU) connector.
*a | Front view of wire harness connector (to Central Gateway ECU [Network Gateway ECU]) |
*b | Front view of DLC3 |
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||
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Result | |||
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OK |
REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) for LHD: Click here |
NG |
REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 6 CAN JUNCTION CONNECTOR) |
CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR)
Reconnect all wire harness connectors.
Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the bus line shorted to GND is connected.
Measure the resistance according to the value(s) in the table below.
*a | Component with harness connected (Central Gateway ECU [Network Gateway ECU]) |
*b | Front view of DLC3 |
Standard Resistance | |||||||
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Tech Tips
If the resistance changes to 200 Ω or higher when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.
Result | |||
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OK |
REPLACE CORRESPONDING ECU OR SENSOR |
NG |
REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH WIRE OR CONNECTOR |