Check Bus 2 Lines for Short Circuit [10/2018 - 10/2019]: 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 IN CAN BUS LINES (NO. 3 CAN JUNCTION CONNECTOR)

Disconnect the cable from the negative (-) auxiliary battery terminal.
Disconnect the No. 3 CAN junction connector.

Measure the resistance according to the value(s) in the table below.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*a	Front view of wire harness connector (to No. 3 CAN Junction Connector)	*b	to No. 6 CAN Junction Connector
*c	to Central Gateway ECU (Network Gateway ECU)	*d	to Rear Hybrid Motor Control Assembly (for AWD)
*e	to Inverter with Converter Assembly	*f	to Brake Booster with Master Cylinder Assembly

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
F88-1 (CANH) - F88-7 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	108 to 132 Ω	No. 6 CAN junction connector
F88-2 (CANH) - F88-8 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	108 to 132 Ω	Central gateway ECU (network gateway ECU)
F88-3 (CANH) - F88-9 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	200 Ω or higher	Rear hybrid motor control assembly*1
F88-4 (CANH) - F88-10 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	200 Ω or higher	Inverter with converter assembly
F88-6 (CANH) - F88-12 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	200 Ω or higher	Brake booster with master cylinder assembly

*1: for AWD

Result

Result	Proceed to
OK	A
NG (Line to central gateway ECU (network gateway ECU))	B
NG (Line to No. 6 CAN junction connector)	C
NG (Line to ECU or sensor)	D

Result:

REPLACE NO. 3 CAN JUNCTION CONNECTOR

Result:

See step 3

Result:

See step 5

Result:

See step 2

CHECK FOR SHORT IN CAN BUS LINES (NO. 3 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.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Front view of wire harness connector
(to No. 3 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance

Tester Connection	Condition	Specified Condition
F88-2 (CANH) - F88-8 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	1 MΩ or higher

Result

Proceed to
OK
NG

Result:

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU). Refer to REMOVAL [10/2018 - 07/2022]

Result:

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

CHECK FOR SHORT IN CAN BUS LINES (NO. 6 CAN JUNCTION CONNECTOR)

Reconnect the F88 No. 3 CAN junction connector.
Disconnect the No. 6 CAN junction connector.

Measure the resistance according to the value(s) in the table below.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

*a	Front view of wire harness connector (to No. 6 CAN Junction Connector)	*b	to No. 3 CAN Junction Connector
*c	to ECM	*d	to Hybrid Vehicle Control ECU

Standard Resistance

Tester Connection	Condition	Specified Condition	Connected to
F93-9 (CANH) - F93-20 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	108 to 132 Ω	No. 3 CAN junction connector
F93-10 (CANH) - F93-21 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	108 to 132 Ω	ECM
F93-11 (CANH) - F93-22 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	200 Ω or higher	Hybrid vehicle control ECU

Result

Result	Proceed to
OK	A
NG (Line to No. 3 CAN junction connector)	B
NG (Line to ECM)	C
NG (Line to ECU or sensor)	D

Result:

REPLACE NO. 6 CAN JUNCTION CONNECTOR

Result:

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - NO. 6 CAN JUNCTION CONNECTOR)

Result:

See step 5

Result:

See step 4

CHECK FOR SHORT IN CAN BUS LINES (NO. 6 CAN JUNCTION CONNECTOR - ECM)

Disconnect the A36 ECM connector.

Measure the resistance according to the value(s) in the table below.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Front view of wire harness connector
(to No. 6 CAN Junction Connector)

to ECM

Standard Resistance

Tester Connection	Condition	Specified Condition
F93-10 (CANH) - F93-21 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	1 MΩ or higher

Result

Proceed to
OK
NG

Result:

REPLACE ECM. Refer to REMOVAL [10/2018 - 07/2022]

Result:

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 6 CAN JUNCTION CONNECTOR - ECM)

CHECK FOR SHORT IN CAN BUS LINES (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 short circuited branch line is connected.
Refer to TERMINALS OF ECU [10/2018 - 10/2019]

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
F61-18 (CA4H) - F61-17 (CA4L)	Cable disconnected from negative (-) auxiliary battery terminal	54 to 69 Ω

*a	Component with harness connected (Central Gateway ECU (Network Gateway ECU))

HINT:

If the resistance becomes normal (between 54 and 69 Ω) 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 in the wire harness and repair or replace the wire harness or connector if necessary.

Result

Proceed to
OK
NG

Result:

REPLACE ECU OR SENSOR

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR