Toyota Avalon (XX50): Check Bus 5 Lines for Short Circuit

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Power Source, Network / Networking / Can Communication System(for Gasoline Model) / 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.	Short in CAN main bus lines Short in CAN branch lines Central gateway ECU (network gateway ECU) Outer mirror control ECU assembly LH (w/ Seat Position Memory System) Outer mirror control ECU assembly RH (w/ Seat Position Memory System) Headlight ECU sub-assembly RH (w/ Cornering Light) Headlight ECU sub-assembly LH (w/ Cornering Light) Position control ECU assembly LH (w/ Seat Position Memory System) Certification ECU (smart key ECU assembly) Multiplex tilt and telescopic ECU (w/ Power Tilt and Power Telescopic System) Meter mirror sub-assembly (w/ Headup Display System) Main body ECU (multiplex network body ECU) Air conditioning amplifier assembly Combination meter assembly No. 3 CAN junction connector No. 6 CAN junction connector No. 2 junction connector No. 3 junction connector

Symptom

Trouble Area

Resistance between terminals 15 (CA5H) and 16 (CA5L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

Short in CAN main bus lines
Short in CAN branch lines
Central gateway ECU (network gateway ECU)
Outer mirror control ECU assembly LH
(w/ Seat Position Memory System)
Outer mirror control ECU assembly RH
(w/ Seat Position Memory System)
Headlight ECU sub-assembly RH
(w/ Cornering Light)
Headlight ECU sub-assembly LH
(w/ Cornering Light)
Position control ECU assembly LH
(w/ Seat Position Memory System)
Certification ECU (smart key ECU assembly)
Multiplex tilt and telescopic ECU
(w/ Power Tilt and Power Telescopic System)
Meter mirror sub-assembly
(w/ Headup Display System)
Main body ECU (multiplex network body ECU)
Air conditioning amplifier assembly
Combination meter assembly
No. 3 CAN junction connector
No. 6 CAN junction connector
No. 2 junction connector
No. 3 junction connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

NOTICE:

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.
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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.
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.
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. 3 CAN JUNCTION CONNECTOR)

(a) Disconnect the cable from the negative (-) battery terminal.

(b) Disconnect the G94 No. 3 CAN junction connector.

*a	Front view of wire harness connector (to No. 3 CAN Junction Connector)	*b	to No. 3 Junction Connector
*c	to Certification ECU (Smart Key ECU Assembly)	*d	to Combination Meter Assembly
*e	to Main Body ECU (Multiplex Network Body ECU)	*f	to Air Conditioning Amplifier Assembly
*g	to Headlight ECU sub-assembly LH (w/ Cornering Light)	*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
G94-3 (CANH) - G94-14 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 3 junction connector
G94-4 (CANH) - G94-15 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Certification ECU (smart key ECU assembly)
G94-5 (CANH) - G94-16 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Combination meter assembly
G94-6 (CANH) - G94-17 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Main body ECU (multiplex network body ECU)
G94-7 (CANH) - G94-18 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Air conditioning amplifier assembly
G94-8 (CANH) - G94-19 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Headlight ECU sub-assembly LH*1
G94-9 (CANH) - G94-20 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Meter mirror sub-assembly*2
G94-10 (CANH) - G94-21 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	to Multiplex tilt and telescopic ECU*3

*1: w/ Cornering Light
*2: w/ Headup Display System
*3: w/ Power Tilt and Power Telescopic System

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

REPLACE NO. 3 CAN JUNCTION CONNECTOR

GO TO STEP 3

GO TO STEP 7

2.	CHECK FOR SHORT IN CAN BUS LINES (NO. 3 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY)

(a) Disconnect the G16 combination meter assembly connector.

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

Front view of wire harness connector

(to No. 3 CAN Junction Connector)

to Combination Meter Assembly

Standard Resistance:

Tester Connection	Condition	Specified Condition
G94-5 (CANH) - G94-16 (CANL)	Cable disconnected from negative (-) battery terminal	1 MΩ or higher

REPLACE COMBINATION METER ASSEMBLY

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY)

3.	CHECK FOR SHORT IN CAN BUS LINES (NO. 3 JUNCTION CONNECTOR)

(a) Reconnect the G94 No. 3 CAN junction connector.

(b) Disconnect the K64 No. 3 junction connector.

Front view of wire harness connector

(to No. 3 Junction Connector)

to Outer Mirror Control ECU Assembly LH

(w/ Seat Position Memory System)

to No. 3 CAN Junction Connector

to No. 2 Junction Connector

Standard Resistance:

Tester Connection	Condition	Specified Condition	Connected to
K64-1 (CANH) - K64-12 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	to Outer mirror control ECU assembly LH*
K64-3 (CANH) - K64-14 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 3 CAN junction connector
K64-4 (CANH) - K64-15 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 2 junction connector

*: w/ Seat Position Memory System

Result	Proceed to
OK	A
NG (Line to No. 3 CAN junction connector)	B
NG (Line to No. 2 junction connector)	C
NG (Line to ECU or sensor)	D

REPLACE NO. 3 JUNCTION CONNECTOR

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

GO TO STEP 7

4.	CHECK FOR SHORT IN CAN BUS LINES (NO. 2 JUNCTION CONNECTOR)

(a) Reconnect the K64 No. 3 junction connector.

(b) Disconnect the K69 No. 2 junction connector.

Front view of wire harness connector

(to No. 2 Junction Connector)

to No. 6 CAN Junction Connector

to No. 3 Junction Connector

to Position Control ECU Assembly LH

(w/ Seat Position Memory System)

Standard Resistance:

Tester Connection	Condition	Specified Condition	Connected to
K69-1 (CANH) - K69-12 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 6 CAN junction connector
K69-2 (CANH) - K69-13 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 3 junction connector
K69-3 (CANH) - K69-14 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Position control ECU assembly LH*

*: w/ Seat Position Memory System

Result	Proceed to
OK	A
NG (Line to No. 3 junction connector)	B
NG (Line to No. 6 CAN junction connector)	C
NG (Line to ECU or sensor)	D

REPLACE NO. 2 JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 2 JUNCTION CONNECTOR - NO. 3 JUNCTION CONNECTOR)

GO TO STEP 7

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

(a) Reconnect the K69 No. 2 junction connector.

(b) Disconnect the K65 No. 6 CAN junction connector.

Front view of wire harness connector

(to No. 6 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

to No. 2 Junction Connector

to Outer Mirror Control ECU Assembly RH

(w/ Seat Position Memory System)

to Headlight ECU Sub-assembly RH

(w/ Cornering Light)

Standard Resistance:

Tester Connection	Condition	Specified Condition	Connected to
K65-1 (CANH) - K65-12 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	Central gateway ECU (network gateway ECU)
K65-2 (CANH) - K65-13 (CANL)	Cable disconnected from negative (-) battery terminal	108 to 132 Ω	No. 2 junction connector
K65-3 (CANH) - K65-14 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Outer mirror control ECU assembly RH*1
K65-5 (CANH) - K65-16 (CANL)	Cable disconnected from negative (-) battery terminal	200 Ω or higher	Headlight ECU sub-assembly RH*2

*1: w/ Seat Position Memory System
*2: w/ Cornering Light

Result	Proceed to
OK	A
NG (Line to central gateway ECU (network gateway ECU))	B
NG (Line to No. 2 junction connector)	C
NG (Line to ECU or sensor)	D

REPLACE NO. 6 CAN JUNCTION CONNECTOR

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 6 CAN JUNCTION CONNECTOR - NO. 2 JUNCTION CONNECTOR)

GO TO STEP 7

6.	CHECK FOR SHORT IN CAN BUS LINES (NO. 6 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

(a) Disconnect the G52 central gateway ECU (network gateway ECU) connector.

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

Front view of wire harness connector

(to No. 6 CAN Junction Connector)

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance:

Tester Connection	Condition	Specified Condition
K65-1 (CANH) - K65-12 (CANL)	Cable disconnected from negative (-) battery terminal	1 MΩ or higher

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 6 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

7.	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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Standard Resistance:

Tester Connection	Condition	Specified Condition
G52-15 (CA5H) - G52-16 (CA5L)	Cable disconnected from negative (-) battery terminal	54 to 69 Ω

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.

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

REPLACE ECU OR SENSOR

REPAIR OR REPLACE HARNESS OR CONNECTOR

Check Bus 5 Line for Short to GND

Clearance Warning ECU Communication Stop Mode. Data List / Active Test. DCM Communication Stop Mode

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