NETWORKING: CAN COMMUNICATION SYSTEM (for HV Model): Battery ECU Communication Stop Mode; 2021 - 2022 MY Corolla Corolla HV [04/2020 - 09/2022]

Last Modified: 07-31-2024	6.11:8.1.0	Doc ID: RM100000001N23B
Model Year Start: 2021	Model: Corolla	Prod Date Range: [04/2020 - 09/2022]
Title: NETWORKING: CAN COMMUNICATION SYSTEM (for HV Model): Battery ECU Communication Stop Mode; 2021 - 2022 MY Corolla Corolla HV [04/2020 - 09/2022]

Battery ECU Communication Stop Mode

DESCRIPTION

Detection Item	Symptom	Trouble Area
Battery ECU Communication Stop Mode	Any of the following conditions are met: Communication stop for "HV Battery" is indicated on the "Communication Bus Check" screen of the Techstream. Click here Communication stop history for "HV Battery" is indicated on the "Communication Bus Check (Detail)" screen of the Techstream. (The Lost Communication Time value for "HV Battery" is 6 or more.) Click here Communication system DTCs (DTCs that start with U) that correspond to "Battery ECU Communication Stop Mode" in "DTC Combination Table" are output. Click here	Battery ECU assembly branch line or connector Power source circuit of battery ECU assembly Battery ECU assembly ground circuit Battery 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 10 minutes 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 (BATTERY ECU ASSEMBLY BRANCH LINE)

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

(b) Disconnect the z28 battery ECU assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z28-9(CA2H) - z28-1(CA2L)	Cable disconnected from negative (-) auxiliary battery terminal	54 to 69 Ω

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

NG

REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (BATTERY ECU ASSEMBLY)

OK

2.	CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

(a) Check the battery ECU assembly power source circuit.

Click here

OK

REPLACE BATTERY ECU ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)