DTC Code | DTC Name |
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Check Bus 1 Line for Short to +B |
DESCRIPTION
There may be a short circuit between one of the CAN bus lines and +B when no resistance exists between terminal 15 (CA5H) of the central gateway ECU and terminal 16 (BAT) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU and terminal 16 (BAT) of the DLC3.
Symptom | Trouble Area |
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No resistance exists between terminal 15 (CA5H) of the central gateway ECU and terminal 16 (BAT) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU and terminal 16 (BAT) of the DLC3. |
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*1: w/ Lexus Safety System +
*2: w/ Blind Spot Monitor System
CAUTION / NOTICE / HINT
Before measuring the resistance of the CAN bus, turn the power 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 (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work (Click here).
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).
After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
DTC check procedure: Turn the power switch on (IG), turn the LDA main switch on, turn the blind spot monitor main switch on, wait at least 52 seconds and then drive the vehicle at a speed of 36 km/h (22 mph) or more for 7 seconds 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 (Click here).
Operating the power switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.
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.
Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines. When the connectors have been disconnected from the CAN junction connector, reconnecting the connectors to non-original positions on the CAN junction connector does not affect system performance. However, it is preferred to reconnect the connectors to their original positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.
PROCEDURE
CHECK FOR SHORT TO +B IN CAN BUS LINE (CENTRAL GATEWAY ECU)
Disconnect the cable from the negative (-) auxiliary battery terminal.
Disconnect the H201 No. 4 CAN junction connector.
Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
Reconnecting the connectors to non-original positions on the CAN junction connector does not affect system performance. However, it is preferred to reconnect the connectors to their original positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.
*a | Rear view of wire harness connector (to No. 4 CAN Junction Connector) |
*b | to Central Gateway ECU |
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
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*a | Component with harness connected (Central Gateway ECU) |
CHECK FOR SHORT TO +B IN CAN BUS LINE (BRANCH LINE)
Reconnect the H201 No. 4 CAN junction connector.
Connect the probes of an electrical tester to terminals 15 (CA5H) and 1 (BATT), or between terminals 16 (CA5L) and 1 (BATT) of the central gateway ECU.
*a | Component with harness connected (Central Gateway ECU) |
While observing the resistance value shown on the tester, disconnect connectors (H203, H204, H205 and U26) from the No. 4 CAN junction connector or No. 5 CAN junction connector one by one until the resistance becomes normal (6 kΩ or higher).
Disconnect the branch line connectors other than CAN main bus line connector.
Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
Reconnecting the connectors to non-original positions on the CAN junction connector does not affect system performance. However, it is preferred to reconnect the connectors to their original positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.
*A | w/ Lexus Safety System + | *B | w/ Blind Spot Monitor System |
*1 | Forward Recognition Camera | *2 | Driving Support ECU Assembly |
*3 | Millimeter Wave Radar Sensor Assembly | *4 | Central Gateway ECU |
*5 | No. 4 CAN Junction Connector | *6 | Hybrid vehicle control ECU assembly |
*7 | Blind Spot Monitor Sensor LH | *8 | No. 5 CAN Junction Connector |
*a | Component without harness connected (No. 4 CAN Junction Connector) |
- | - |
No. 4 CAN Junction Connector | Code | Color (CANH Side) | Color (CANL Side) |
---|---|---|---|
Millimeter wave radar sensor assembly* | H204 | Y | LG |
Central gateway ECU | H201 | L | LG |
No. 5 CAN junction connector | H202 | G | LG |
Forward recognition camera* | H203 | R | LG |
Driving support ECU assembly* | H205 | B | LG |
*: w/ Lexus Safety System +
*a | Component without harness connected (No. 5 CAN Junction Connector) |
- | - |
CAN Junction Connector RH1 Side | Code | Color (CANH Side) | Color (CANL Side) |
---|---|---|---|
Blind spot monitor sensor LH* | U26 | V | LG |
Hybrid vehicle control ECU assembly | U28 | Y | LG |
No. 4 CAN junction connector | U25 | G | LG |
*: w/ Blind Spot Monitor System
Do not reconnect the disconnected connectors until this inspection is complete because there may be a short to +B in 2 or more CAN bus lines.
Result | ||||||
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When there is a short to +B in one or more of the bus lines that connect to an ECU or sensor:
Reconnect all of the connectors to the CAN junction connector, except for the one that was disconnected last (the bus line that is shorted to +B). Check that the resistance shown on the tester is normal (6 kΩ or higher) to confirm that there is a short to +B in the one bus line only.
CHECK FOR SHORT TO +B IN CAN BUS LINE (HYBRID VEHICLE CONTROL ECU ASSEMBLY)
Reconnect the all connector of the No. 4 CAN junction connector and No. 5 CAN junction connector.
Disconnect the U28 No. 5 CAN junction connector.
Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
Reconnecting the connectors to non-original positions on the CAN junction connector does not affect system performance. However, it is preferred to reconnect the connectors to their original positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.
*a | Rear view of wire harness connector (to No. 5 CAN Junction Connector) |
*b | to Hybrid Vehicle Control ECU Assembly |
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
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*a | Component with harness connected (Central Gateway ECU) |
Result | ||||||
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CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 4 CAN J/C)
Reconnect the U28 No. 5 CAN junction connector.
Disconnect the H202 No. 4 CAN junction connector.
Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
Reconnecting the connectors to non-original positions on the CAN junction connector does not affect system performance. However, it is preferred to reconnect the connectors to their original positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.
*a | Rear view of wire harness connector (to No. 4 CAN Junction Connector) |
*b | to No. 5 CAN Junction Connector |
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
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*a | Component with harness connected (Central Gateway ECU) |
REPLACE NO. 4 CAN JUNCTION CONNECTOR
CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 4 CAN J/C - NO. 5 CAN J/C)
Reconnect the H202 No. 4 CAN junction connector.
Disconnect the U25 No. 5 CAN junction connector.
Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
Reconnecting the connectors to non-original positions on the CAN junction connector does not affect system performance. However, it is preferred to reconnect the connectors to their original positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.
*a | Rear view of wire harness connector (to No. 5 CAN Junction Connector) |
*b | to No. 4 CAN Junction Connector |
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
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*a | Component with harness connected (Central Gateway ECU) |
REPLACE NO. 5 CAN JUNCTION CONNECTOR
REPAIR OR REPLACE CAN MAIN BUS LINE (NO. 4 CAN J/C - NO. 5 CAN J/C)
CHECK FOR SHORT TO +B IN CAN BUS LINE (ECU, SENSOR)
Reconnect the connector of the branch line that is shorted to +B to the CAN junction connector (the connector that caused the bus line resistance to change to 6 kΩ or higher when it was disconnected).
Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the bus line shorted to +B is connected (Click here).
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
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*a | Component with harness connected (Central Gateway ECU) |
If the resistance changes to 6 kΩ or higher when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.
REPLACE CORRESPONDING ECU OR SENSOR
REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINE OR CONNECTOR
CHECK FOR SHORT TO +B IN CAN BUS LINE (HYBRID VEHICLE CONTROL ECU ASSEMBLY - NO. 5 CAN J/C)
Reconnect the U28 No. 5 CAN junction connector
Disconnect the H211 hybrid vehicle control ECU assembly connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
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*a | Component with harness connected (Central Gateway ECU) |
REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY (Click here)
REPAIR OR REPLACE CAN MAIN BUS LINE (HYBRID VEHICLE CONTROL ECU ASSEMBLY)
CHECK FOR SHORT TO +B IN CAN BUS LINE (CENTRAL GATEWAY ECU - NO. 4 CAN J/C)
Reconnect the H201 No. 4 CAN junction connector.
Disconnect the H195 central gateway ECU connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | |||||||||
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*a | Front view of wire harness connector (to Central Gateway ECU) |
REPLACE CENTRAL GATEWAY ECU (Click here)
REPAIR OR REPLACE CAN MAIN BUS LINE (CENTRAL GATEWAY ECU)