Check CAN Bus Lines for Short Circuit

NETWORKING: CAN COMMUNICATION SYSTEM: Check CAN Bus Lines for Short Circuit
- Check CAN Bus Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the V bus main lines and/or CAN branch lines when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 54 Ohms.

* *1: w/ Blind spot monitor system

* *2: w/ Intuitive parking assist system

* *3: w/ Smart key system

* *4: for Navigation receiver type

* *5: for Radio and display type w/ intuitive parking assist system

* *6: for Radio and display type w/o intuitive parking assist system

* *7: for 2AR-FE w/ wireless door lock system

* *8: for 2AR-FE w/o wireless door lock system

* *9: for 2GR-FE w/ wireless door lock system

* *10: Separate type yaw rate sensor

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:
* 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, 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 Service Precautions.
* 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 How to Proceed With Troubleshooting.
* 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, turn the blind spot monitor system on using the blind spot monitor main switch (ON/OFF switch), wait at least 31 seconds, and then drive the vehicle at a speed of 20 km/h (12 mph) or more at least 5 minutes. Check that the warning light remains off after turning off following the initial light check.
* After the repair, perform CAN Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed Diagnosis System.

HINT
* Operating the ignition switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.
* Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.
* Connectors that connect to the CAN junction connector can be distinguished by color of their CAN bus lines. When the connectors have been disconnected from the CAN junction connector, reconnecting the connectors to non-original positions on the CAN junction connector does not affect system performance. However, it is preferred to reconnect the connectors to their original positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.

PROCEDURE

1. CHECK FOR SHORT IN CAN BUS LINES (DLC3 BRANCH LINE)

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

(b) Disconnect the DLC3 branch line connector (I96) from the CAN No. 1 junction connector.

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NOTICE:
* Before disconnecting the connector, make a note of where it is connected.
* Reconnect the connector to its original position.

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

Standard Resistance:

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NG -- REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO DLC3
OK -- Continue to next step.

2. CHECK FOR SHORT IN CAN BUS LINES (BRANCH LINE)

(a) Reconnect the DLC3 branch line connector (I96) to the CAN No. 1 junction connector.

(b) Connect the probes of an ohmmeter to terminals 6 (CANH) and 14 (CANL) of the DLC3.

Text in Illustration

(c) While observing the resistance value shown on the tester, disconnect connectors I95, I97, I100, I102, I103, I105, I106, I107, I108, I111 and I173 from the CAN No. 1 junction connector or CAN No. 2 junction connector one by one until the resistance becomes normal (between 54 and 69 Ohms).

HINT
Disconnect the branch line connectors other than those of the DLC3.

Text in Illustration

Wiring Color

*1: for 2AR-FE w/ wireless door lock system

*2: for 2AR-FE w/o wireless door lock system

*3: for 2GR-FE w/ wireless door lock system

*4: Separate type yaw rate sensor

Text in Illustration

Wiring Color

*1: for Navigation receiver type

*2: for Radio and display type w/ intuitive parking assist system

*3: for Radio and display type w/o intuitive parking assist system

*4: w/ Blind spot monitor system

*5: w/ Smart key system

*6: w/ Intuitive parking assist system

NOTICE:
Do not reconnect the disconnected connectors until this inspection is complete because there may be a short in 2 or more branch lines.

Result:

(d) When there is a short in one or more of the branch lines:

(1) Reconnect all of the connectors to the CAN J/C, except for the one that was disconnected last (the short-circuited bus line). Check that the resistance shown on the tester is normal (between 54 and 69 Ohms) to confirm that there is a short in the one branch line only.

HINT
* Connectors that connect to the CAN junction connector can be distinguished by the color of their CAN bus lines.
* Reconnecting the connectors to non-original positions on the CAN junction connector does not affect system performance. However, it is preferred to reconnect the connectors to their original positions to avoid negative effects on the wiring such as tension on the wiring harnesses, and to make future maintenance easier.

B -- CHECK FOR SHORT IN CAN BUS LINES (ECU, SENSOR)
A -- Continue to next step.

3. CHECK FOR SHORT IN CAN BUS LINES (COMBINATION METER ASSEMBLY MAIN BUS LINE)

(a) Disconnect the combination meter assembly main bus line connector (I94) from the CAN No. 1 junction connector.

Text in Illustration

NOTICE:
* Before disconnecting the connector, make a note of where it is connected.
* Reconnect the connector to its original position.

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

Text in Illustration

Standard Resistance:

Result:

B -- CHECK FOR SHORT IN CAN BUS LINES (COMBINATION METER ASSEMBLY)
A -- Continue to next step.

4. CHECK FOR SHORT IN CAN BUS LINES (ECM MAIN BUS LINE)

(a) Disconnect the ECM main bus line connector (I104) from the CAN No. 2 junction connector.

Text in Illustration

Standard Resistance:

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HINT
Measure the resistance with the combination meter assembly main bus line connector (F) disconnected.

Result:

B -- CHECK FOR SHORT IN CAN BUS LINES (ECM)
A -- Continue to next step.

5. CHECK CAN NO. 1 JUNCTION CONNECTOR

(a) Disconnect the CAN main bus line connector (I93) from the CAN No. 1 junction connector.

Text in Illustration

Standard Resistance:

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NG -- REPLACE CAN NO. 1 JUNCTION CONNECTOR
OK -- Continue to next step.

6. CHECK CAN NO. 2 JUNCTION CONNECTOR (CAN NO. 1 J/C - CAN NO. 2 J/C)

(a) Reconnect the CAN main bus line connector (I93) to the CAN No. 1 junction connector.

(b) Disconnect the CAN main bus line connector (I101) from the CAN No. 2 junction connector.

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Standard Resistance:

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NG -- REPAIR OR REPLACE CAN BUS MAIN LINES (CAN NO. 1 JUNCTION CONNECTOR - CAN NO. 2 JUNCTION CONNECTOR)

OK -- REPLACE CAN NO. 2 JUNCTION CONNECTOR

7. CHECK FOR SHORT IN CAN BUS LINES (ECU, SENSOR)

(a) Reconnect the connector for the short-circuited branch line to the CAN J/C (the connector that caused the bus line resistance to become normal (between 54 and 69 Ohms) when it was disconnected).

(b) Disconnect the connector that includes the DLC3 connected CAN lines (such as CANH and CANL) from the ECU (or sensor) to which the short-circuited branch line is connected CAN Communication System.

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

Standard Resistance:

Text in Illustration

HINT
If the resistance becomes normal (between 54 and 69 Ohms) when the connector is disconnected from the ECU (or sensor), there may be a short in the ECU (or sensor).

NG -- REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINES OR CONNECTOR

OK -- REPLACE CORRESPONDING ECU OR SENSOR

8. CHECK FOR SHORT IN CAN BUS LINES (COMBINATION METER ASSEMBLY)

(a) Reconnect the combination meter assembly main bus line connector (I94) to the CAN No. 1 junction connector.

(b) Disconnect the combination meter assembly connector (I18).

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

Standard Resistance:

Text in Illustration

HINT
If the resistance becomes normal (between 108 to 132 Ohms) when the connector is disconnected, there may be a short in the combination meter assembly.

NG -- REPAIR OR REPLACE CAN BUS MAIN LINES (COMBINATION METER ASSEMBLY MAIN BUS LINES)

OK -- REPLACE COMBINATION METER ASSEMBLY Removal

9. CHECK FOR SHORT IN CAN BUS LINES (ECM)

(a) Reconnect the ECM main bus line connector (I104) to the CAN No. 2 junction connector.

(b) Disconnect the ECM connector (A25).

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

Standard Resistance:

Text in Illustration

Result:

HINT
* Measure the resistance with the combination meter assembly main bus line connector (I94) disconnected.
* If the resistance changes to 1 Mohms or more when the connector is disconnected, there may be a short in the ECM.

B -- REPLACE ECM Removal

C -- REPAIR OR REPLACE CAN BUS MAIN LINES (ECM MAIN BUS LINES)

A -- REPLACE ECM Removal