Check Bus 4 Line for Short to +B [10/2018 - 08/2021]: Procedure
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2024 Lexus UX 250h, 2023 Lexus UX 250h, 2022 Lexus UX 250h, 2021 Lexus UX 250h, and 2020 Lexus UX 250h. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR)
- Disconnect the cable from the negative (-) auxiliary battery terminal.
- Disconnect the No. 7 CAN junction connector.
- Measure the resistance according to the value(s) in the table below.
*1 DLC3 - - *a Front view of wire harness connector
(to No. 7 CAN Junction Connector)*b to No. 4 CAN Junction Connector *c to Central Gateway ECU (Network Gateway ECU) *d to Hybrid Vehicle Control ECU *e to Tire Pressure ECU and Receiver *f to ECM *g to Occupant Detection ECU *h to Brake Booster with Master Cylinder Assembly *i to Brake Actuator Assembly - - Standard Resistance
Tester Connection Condition Specified Condition Connected to F94-1 (CANH) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher No. 4 CAN junction connector F94-11 (CANL) - F58-16 (BAT) F94-2 (CANH) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Central Gateway ECU (Network Gateway ECU) F94-12 (CANL) - F58-16 (BAT) F94-3 (CANH) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Hybrid vehicle control ECU F94-13 (CANL) - F58-16 (BAT) F94-4 (CANH) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Tire Pressure ECU and Receiver F94-14 (CANL) - F58-16 (BAT) F94-5 (CANH) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher ECM F94-15 (CANL) - F58-16 (BAT) F94-6 (CANH) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Occupant Detection ECU F94-16 (CANL) - F58-16 (BAT) F94-7 (CANH) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Brake Booster with Master Cylinder Assembly F94-17 (CANL) - F58-16 (BAT) F94-9 (CANH) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Brake Actuator Assembly F94-19 (CANL) - F58-16 (BAT) Result
Result Proceed to OK A NG (Line to central gateway ECU (network gateway ECU)) B NG (Line to No. 4 CAN junction connector) C NG (Line to ECU or sensor) D
Result:
A
REPLACE NO. 7 CAN JUNCTION CONNECTOR
Result:
C
See step 3
Result:
D
See step 4
Result:
B
See step 2
- CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))
- Disconnect the F61 central gateway ECU (network gateway ECU) connector.
- Measure the resistance according to the value(s) in the table below.
*1 DLC3 - - *a Front view of wire harness connector
(to No. 7 CAN Junction Connector)*b to Central Gateway ECU (Network Gateway ECU) Standard Resistance
Tester Connection Condition Specified Condition F94-2 (CANH) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher F94-12 (CANL) - F58-16 (BAT) Result
Proceed to OK NG
Result:
OK
REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU). Refer to REMOVAL [10/2018 - 07/2022]
Result:
NG
REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))
- CHECK FOR SHORT TO +B IN CAN BUS LINE (NO. 4 CAN JUNCTION CONNECTOR)
- Disconnect the No. 4 CAN junction connector.
- Measure the resistance according to the value(s) in the table below.
*1 DLC3 - - *a Front view of wire harness connector
(to No. 4 CAN Junction Connector)*b to No. 7 CAN Junction Connector *c to Airbag ECU Assembly *d to Power Steering ECU with Motor Assembly *e to Steering Sensor - - Standard Resistance
Tester Connection Condition Specified Condition Connected to F89-5 (CANH) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher No. 7 CAN junction connector F89-16 (CANL) - F58-16 (BAT) F89-6 (CANH) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Airbag ECU Assembly F89-17 (CANL) - F58-16 (BAT) F89-7 (CANH) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Power Steering ECU with Motor Assembly F89-18 (CANL) - F58-16 (BAT) F89-8 (CANH) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Steering Sensor F89-19 (CANL) - F58-16 (BAT) Result
Result Proceed to OK A NG (Line to No. 7 CAN junction connector) B NG (Line to ECU or sensor) C
Result:
A
REPLACE NO. 4 CAN JUNCTION CONNECTOR
Result:
B
REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 7 CAN JUNCTION CONNECTOR)
Result:
C
See step 4
- CHECK FOR SHORT TO +B IN CAN BUS LINE (ECU OR 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 +B is connected.
Refer to TERMINALS OF ECU [10/2018 - 10/2019] , or refer to TERMINALS OF ECU [10/2019 - 08/2021]
- Measure the resistance according to the value(s) in the table below.
*1 DLC3 - - *a Component with harness connected
(Central Gateway ECU (Network Gateway ECU))- - Standard Resistance
Tester Connection Condition Specified Condition F61-22 (CA2H) - F58-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher F61-7 (CA2L) - F58-16 (BAT) HINT:
- 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.
- If the resistance does not become normal when the connector is disconnected from the ECU or sensor, check for a short to +B in the wire harness and repair or replace the wire harness or connector if necessary.
Result
Proceed to OK NG
Result:
OK
REPLACE ECU OR SENSOR
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR