- Main body ECU (multiplex network body ECU) main line or connector
- Power source circuit of main body ECU (multiplex network body ECU) or power distribution box assembly
- Main body ECU (multiplex network body ECU) or power distribution box assembly ground circuit
- Main body ECU (multiplex network body ECU) or power distribution box assembly
| Last Modified: 06-05-2026 | 6.11:8.1.0 | Doc ID: RM100000002DUJT |
| Model Year Start: 2024 | Model: GR Corolla | Prod Date Range: [08/2023 - ] |
| Title: NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): Main Body ECU Communication Stop Mode; 2024 - 2026 MY GR Corolla Corolla Corolla Hatchback [08/2023 - ] | ||
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Main Body ECU Communication Stop Mode |
DESCRIPTION
|
Detection Item |
Symptom |
Trouble Area |
|---|---|---|
|
Main Body ECU Communication Stop Mode |
Communication stop for "Main Body" is indicated on the "Communication Bus Check" screen of the GTS.
Click here
|
|
WIRING DIAGRAM
except G16E-GTS
for G16E-GTS
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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![2024 - 2025 MY GR Corolla Corolla Corolla Hatchback [08/2023 - 09/2024]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): HOW TO PROCEED WITH TROUBLESHOOTING](/t3Portal/stylegraphics/info.gif)
- Before measuring the resistance of the CAN bus, turn the ignition 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 10 minutes or more before measuring the resistance.
-
After the ignition switch is turned off, there may be a waiting time before disconnecting the negative (-) battery terminal.
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When disconnecting and reconnecting the battery.
HINT:
When disconnecting and reconnecting the battery, there is an automatic learning function that completes learning when the respective system is used.
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-
Some parts must be initialized and set when replacing or removing and installing parts.
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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 ignition switch to ON 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.
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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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- Inspect the fuses for circuits related to this system before performing the following procedure.
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Before replacing the main body ECU (multiplex network body ECU), 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 OPEN IN CAN BUS LINES (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) MAIN LINE) |
(a) Disconnect the cable from the negative (-) battery terminal.
(b) Disconnect the I85 main body ECU (multiplex network body ECU) connector.
|
(c) Measure the resistance according to the value(s) in the table below. Standard Resistance
|
|
| NG |
|
REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)) |
|
|
2. |
CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) |
(a) Remove the main body ECU (multiplex network body ECU).
Click here
|
(b) Measure the resistance according to the value(s) in the table below. Standard Resistance
NOTICE: Perform this inspection with the wire harness connected to the power distribution box assembly. |
|
(c) Reconnect the cable to the negative (-) battery terminal.
(d) Measure the voltage according to the value(s) in the table below.
Standard Voltage
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
MB-26 (BECU) - Body ground |
Always |
11 to 14 V |
NOTICE:
Perform this inspection with the wire harness connected to the power distribution box assembly.
Result
|
Result |
Proceed to |
|---|---|
|
OK |
A |
|
NG (BECU) |
B |
|
NG (GND1 or GND2) |
C |
| A |
|
| C |
|
|
|
3. |
CHECK HARNESS AND CONNECTOR (BECU SIGNAL CIRCUIT) |
(a) Disconnect the cable from the negative (-) battery terminal.
(b) Disconnect the 8F power distribution box assembly connector.
(c) Reconnect the cable to the negative (-) battery terminal.
|
(d) Measure the voltage according to the value(s) in the table below. Standard Voltage
|
|
| OK |
|
REPLACE POWER DISTRIBUTION BOX ASSEMBLY
Click here
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR (BECU SIGNAL CIRCUIT) |
|
4. |
CHECK HARNESS AND CONNECTOR (GROUND CIRCUIT) |
(a) Disconnect the cable from the negative (-) battery terminal.
(b) Disconnect the 8D power distribution box assembly connector.
|
(c) Measure the resistance according to the value(s) in the table below. Standard Resistance
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