- Short in CAN main bus lines
- Short in CAN branch lines
- Central gateway ECU (network gateway ECU)
- Air conditioning amplifier assembly
-
Certification ECU (smart key ECU assembly)
(w/ Smart Key System)
- Main body ECU (multiplex network body ECU)
- Combination meter assembly
-
Meter mirror sub-assembly
(w/ Headup Display System)
-
Headlight ECU sub-assembly RH
(w/ AFS)
-
Headlight ECU sub-assembly LH
(w/ AFS)
- No. 3 CAN junction connector
| Last Modified: 05-13-2024 | 6.11:8.1.0 | Doc ID: RM100000001GMBG |
| Model Year Start: 2020 | Model: GR Corolla | Prod Date Range: [01/2019 - 09/2022] |
| Title: NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): Check Bus 5 Lines for Short Circuit; 2020 - 2022 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 09/2022] | ||
|
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. |
|
WIRING DIAGRAM
w/ Smart Key System
w/o Smart Key System
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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![2019 - 2022 MY Corolla Corolla Hatchback GR Corolla [06/2018 - 09/2022]; 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 1 minute or more before measuring the resistance.
-
After turning the ignition 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.
Click here
-
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.
-
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.*
Click here
- *: w/ Smart Key System
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 VEHICLE TYPE |
(a) Check vehicle type.
|
Result |
Proceed to |
|---|---|
|
w/ Smart Key System |
A |
|
w/o Smart Key System |
B |
| B |
|
|
|
2. |
CHECK FOR SHORT IN CAN BUS LINES (NO. 3 CAN JUNCTION CONNECTOR) |
(a) Disconnect the cable from the negative (-) battery terminal.
(b) Disconnect the I94 No. 3 CAN junction connector.
(c) Measure the resistance according to the value(s) in the table below.
|
*a |
Front view of wire harness connector (to No. 3 CAN Junction Connector) |
*b |
to Combination Meter Assembly |
|
*c |
to Main Body ECU (Multiplex Network Body ECU) |
*d |
to Meter Mirror Sub-assembly (w/ Headup Display System) |
|
*e |
to Air Conditioning Amplifier Assembly |
*f |
to Certification ECU (Smart Key ECU Assembly) |
|
*g |
to Central gateway ECU (Network Gateway ECU) |
*h |
to Headlight ECU Sub-assembly RH (w/ AFS) |
|
*i |
to Headlight ECU Sub-assembly LH (w/ AFS) |
- |
- |
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
Connected to |
|---|---|---|---|
|
I94-1 (CANH) - I94-11 (CANL) |
Cable disconnected from negative (-) battery terminal |
108 to 132 Ω |
Combination meter assembly |
|
I94-2 (CANH) - I94-12 (CANL) |
Cable disconnected from negative (-) battery terminal |
200 Ω or higher |
Main body ECU (multiplex network body ECU) |
|
I94-3 (CANH) - I94-13 (CANL) |
Cable disconnected from negative (-) battery terminal |
200 Ω or higher |
Meter mirror sub-assembly*1 |
|
I94-4 (CANH) - I94-14 (CANL) |
Cable disconnected from negative (-) battery terminal |
200 Ω or higher |
Air conditioning amplifier assembly |
|
I94-5 (CANH) - I94-15 (CANL) |
Cable disconnected from negative (-) battery terminal |
200 Ω or higher |
Certification ECU (smart key ECU assembly) |
|
I94-6 (CANH) - I94-16 (CANL) |
Cable disconnected from negative (-) battery terminal |
108 to 132 Ω |
Central gateway ECU (network gateway ECU) |
|
I94-7 (CANH) - I94-17 (CANL) |
Cable disconnected from negative (-) battery terminal |
200 Ω or higher |
Headlight ECU sub-assembly RH*2 |
|
I94-8 (CANH) - I94-18 (CANL) |
Cable disconnected from negative (-) battery terminal |
200 Ω or higher |
Headlight ECU sub-assembly LH*2 |
- *1: w/ Headup Display System
- *2: w/ AFS
|
Result |
Proceed to |
|---|---|
|
OK |
A |
|
NG (Line to central gateway ECU (network gateway ECU)) |
B |
|
NG (Line to Combination meter assembly) |
C |
|
NG (Line to ECU or sensor) |
D |
| A |
|
REPLACE NO. 3 CAN JUNCTION CONNECTOR |
| C |
|
| D |
|
|
|
3. |
CHECK FOR SHORT IN CAN BUS LINES (NO. 3 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) |
(a) Disconnect the I53 central gateway ECU (network gateway ECU) connector.
(b) Measure the resistance according to the value(s) in the table below.
|
*a |
Front view of wire harness connector (to No. 3 CAN Junction Connector) |
*b |
to Central Gateway ECU (Network Gateway ECU) |
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
I94-6 (CANH) - I94-16 (CANL) |
Cable disconnected from negative (-) battery terminal |
1 MΩ or higher |
| OK |
|
| NG |
|
REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) |
|
4. |
CHECK FOR SHORT IN CAN BUS LINES (NO. 3 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY) |
(a) Disconnect the I4 combination meter assembly connector.
(b) Measure the resistance according to the value(s) in the table below.
|
*a |
Front view of wire harness connector (to No. 3 CAN Junction Connector) |
*b |
to Combination Meter Assembly |
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
I94-1 (CANH) - I94-11 (CANL) |
Cable disconnected from negative (-) battery terminal |
1 MΩ or higher |
| OK |
|
REPLACE COMBINATION METER ASSEMBLY
|
| NG |
|
REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY) |
|
5. |
CHECK FOR SHORT IN CAN BUS LINES (NO. 3 CAN JUNCTION CONNECTOR) |
(a) Disconnect the cable from the negative (-) battery terminal.
(b) Disconnect the I125 No. 3 CAN junction connector.
(c) Measure the resistance according to the value(s) in the table below.
|
*a |
Front view of wire harness connector (to No. 3 CAN Junction Connector) |
*b |
to Combination Meter Assembly |
|
*c |
to Main Body ECU (Multiplex Network Body ECU) |
*d |
to Air Conditioning Amplifier Assembly |
|
*e |
to Central gateway ECU (Network Gateway ECU) |
- |
- |
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
Connected to |
|---|---|---|---|
|
I125-2 (CANH) - I125-13 (CANL) |
Cable disconnected from negative (-) battery terminal |
108 to 132 Ω |
Combination meter assembly |
|
I125-3 (CANH) - I125-14 (CANL) |
Cable disconnected from negative (-) battery terminal |
200 Ω or higher |
Main body ECU (multiplex network body ECU) |
|
I125-5 (CANH) - I125-16 (CANL) |
Cable disconnected from negative (-) battery terminal |
200 Ω or higher |
Air conditioning amplifier assembly |
|
I125-7 (CANH) - I125-18 (CANL) |
Cable disconnected from negative (-) battery terminal |
108 to 132 Ω |
Central gateway ECU (network gateway ECU) |
|
Result |
Proceed to |
|---|---|
|
OK |
A |
|
NG (Line to central gateway ECU (network gateway ECU)) |
B |
|
NG (Line to Combination meter assembly) |
C |
|
NG (Line to ECU or sensor) |
D |
| A |
|
REPLACE NO. 3 CAN JUNCTION CONNECTOR |
| C |
|
| D |
|
|
|
6. |
CHECK FOR SHORT IN CAN BUS LINES (NO. 3 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) |
(a) Disconnect the I53 central gateway ECU (network gateway ECU) connector.
(b) Measure the resistance according to the value(s) in the table below.
|
*a |
Front view of wire harness connector (to No. 3 CAN Junction Connector) |
*b |
to Central Gateway ECU (Network Gateway ECU) |
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
I125-7 (CANH) - I125-18 (CANL) |
Cable disconnected from negative (-) battery terminal |
1 MΩ or higher |
| OK |
|
| NG |
|
REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) |
|
7. |
CHECK FOR SHORT IN CAN BUS LINES (NO. 3 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY) |
(a) Disconnect the I4 combination meter assembly connector.
(b) Measure the resistance according to the value(s) in the table below.
|
*a |
Front view of wire harness connector (to No. 3 CAN Junction Connector) |
*b |
to Combination Meter Assembly |
Standard Resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
I125-2 (CANH) - I125-13 (CANL) |
Cable disconnected from negative (-) battery terminal |
1 MΩ or higher |
| OK |
|
REPLACE COMBINATION METER ASSEMBLY
|
| NG |
|
REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY) |
|
8. |
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.
Click here
|
(c) Measure the resistance according to the value(s) in the table below. Standard Resistance:
HINT:
|
|
| OK |
|
REPLACE ECU OR SENSOR |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|