Toyota Avalon (XX50): Driving Support ECU Communication Stop Mode. Dtc Check / Clear. ECM Communication Stop Mode

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Power Source, Network / Networking / Can Communication System(for Hv Model) / Driving Support ECU Communication Stop Mode. Dtc Check / Clear. ECM Communication Stop Mode

Driving Support ECU Communication Stop Mode

DESCRIPTION

Detection Item	Symptom	Trouble Area
Driving Support ECU Communication Stop Mode	Any of the following conditions are met: Communication stop for "Driving Support (CruiseControl-ACC)" is indicated on the "Communication Bus Check" screen of the Techstream. Click here Communication stop history for "Driving Support (CruiseControl-ACC)" is indicated on the "Communication Bus Check (Detail)" screen of the Techstream. (The Lost Communication Time value for "Driving Support (CruiseControl-ACC)" is 6 or more.) Click here Communication system DTCs (DTCs that start with U) that correspond to "Driving Support ECU Communication Stop Mode" in "DTC Combination Table" are output.	Driving support ECU assembly branch line or connector Power source circuit of driving support ECU assembly Driving support ECU assembly ground circuit Driving support ECU assembly

Detection Item

Symptom

Trouble Area

Driving Support ECU Communication Stop Mode

Any of the following conditions are met:

Communication stop for "Driving Support (CruiseControl-ACC)" is indicated on the "Communication Bus Check" screen of the Techstream.
Click here
Communication stop history for "Driving Support (CruiseControl-ACC)" is indicated on the "Communication Bus Check (Detail)" screen of the Techstream. (The Lost Communication Time value for "Driving Support (CruiseControl-ACC)" is 6 or more.)
Click here
Communication system DTCs (DTCs that start with U) that correspond to "Driving Support ECU Communication Stop Mode" in "DTC Combination Table" are output.

Driving support ECU assembly branch line or connector
Power source circuit of driving support ECU assembly
Driving support ECU assembly ground circuit
Driving support ECU assembly

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.
Click here
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
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) 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.
Click here
Inspect the fuses for circuits related to this system before performing the following procedure.

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 OPEN IN CAN BUS LINES (DRIVING SUPPORT ECU ASSEMBLY BRANCH LINE)

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

(b) Disconnect the G39 driving support ECU assembly connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
G39-10 (CA2H) - G39-11 (CA2L)	Cable disconnected from negative (-) auxiliary battery terminal	54 to 69 Ω

*a	Front view of wire harness connector (to Driving Support ECU Assembly)

REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (DRIVING SUPPORT ECU ASSEMBLY)

2.	CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
G39-28 (GND) - Body ground	Cable disconnected from negative (-) auxiliary battery terminal	Below 1 Ω

*a	Front view of wire harness connector (to Driving Support ECU Assembly)

(b) Reconnect the cable to the negative (-) auxiliary battery terminal.

Standard Voltage:

Tester Connection	Condition	Specified Condition
G39-7 (B) - Body ground	Power switch on (IG)	11 to 14 V

REPLACE DRIVING SUPPORT ECU ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

Dtc Check / Clear

DTC CHECK / CLEAR

CHECK FOR DTC

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(d) Enter the following menus: Body Electrical / Central Gateway / Trouble Codes.

Body Electrical > Central Gateway > Trouble Codes

(e) Read the DTCs.

CLEAR DTC

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(d) Enter the following menus: Body Electrical / Central Gateway / Trouble Codes.

Body Electrical > Central Gateway > Trouble Codes

(e) Clear the DTCs.

Body Electrical > Central Gateway > Clear DTCs

ECM Communication Stop Mode

DESCRIPTION

Detection Item	Symptom	Trouble Area
ECM Communication Stop Mode	Any of the following conditions are met: Communication stop for "ECM (Engine)" is indicated on the "Communication Bus Check" screen of the Techstream. Click here Communication stop history for "ECM (Engine)" is indicated on the "Communication Bus Check (Detail)" screen of the Techstream. (The Lost Communication Time value for "ECM (Engine)" is 6 or more.) Click here Communication system DTCs (DTCs that start with U) that correspond to "ECM Communication Stop Mode" in "DTC Combination Table" are output. Click here	ECM main line or connector ECM branch line or connector Power source circuit of ECM ECM ground circuit ECM

Detection Item

Symptom

Trouble Area

ECM Communication Stop Mode

Any of the following conditions are met:

Communication stop for "ECM (Engine)" is indicated on the "Communication Bus Check" screen of the Techstream.
Click here
Communication stop history for "ECM (Engine)" is indicated on the "Communication Bus Check (Detail)" screen of the Techstream. (The Lost Communication Time value for "ECM (Engine)" is 6 or more.)
Click here
Communication system DTCs (DTCs that start with U) that correspond to "ECM Communication Stop Mode" in "DTC Combination Table" are output.
Click here

ECM main line or connector
ECM branch line or connector
Power source circuit of ECM
ECM ground circuit
ECM

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.
Click here
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
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) 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.
Click here
Inspect the fuses for circuits related to this system before performing the following procedure.

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 OPEN IN CAN BUS LINES (ECM MAIN LINE AND BRANCH LINE)

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

(b) Disconnect the A19 ECM connector.

Standard Resistance:

Bus 2 Main Lines

Tester Connection	Condition	Specified Condition
A19-8 (CANH) - A19-18 (CANL)	Cable disconnected from negative (-) auxiliary battery terminal	108 to 132 Ω

Bus 4 Branch Lines

Tester Connection	Condition	Specified Condition
A19-7 (CAN+) - A19-17 (CAN-)	Cable disconnected from negative (-) auxiliary battery terminal	54 to 69 Ω

*a	Front view of wire harness connector (to ECM)

Result	Proceed to
OK	A
NG (Bus 2 main line)	B
NG (Bus 4 branch line)	C

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (ECM)

REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (ECM)

2.	CHECK ECM POWER SOURCE CIRCUIT

(a) Check the ECM power source circuit.

Click here

REPLACE ECM

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

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