Check CAN Bus Line for Short to +B

NETWORKING: CAN COMMUNICATION SYSTEM: Check CAN Bus Line for Short to +B
- Check CAN Bus Line for Short to +B

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and +B when no resistance exists between terminals 6 (CANH) and 16 (BAT) or 14 (CANL) and 16 (BAT) of the DLC3.

* *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/ Intuitive parking assist system

* *5: Separate type yaw rate sensor

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:
* 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, 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 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 power switch on (IG), turn the cruise control main switch on, turn the blind spot monitor main switch on, wait at least 60 seconds and then drive the vehicle at a speed of 20 km/h (12 mph) or more for at least 11 seconds.
* 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 power 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 TO +B IN CAN BUS LINE (DLC3 BRANCH LINE)

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

(b) Disconnect the DLC3 branch line connector (I96) from the CAN junction LH connector.

Text in Illustration

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:

Text in Illustration

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

2. CHECK FOR SHORT TO +B IN CAN BUS LINE

(a) Reconnect the DLC3 branch line connector (I96) to the CAN junction LH connector.

(b) Disconnect the connectors from the CAN junction LH connector and CAN junction RH connector one at a time.

HINT
Disconnect the ECU and sensor connectors other than the DLC3 branch lines and CAN main bus lines between the CAN junction LH connector and CAN junction RH connector.

Text in Illustration

(c) Using an ohmmeter, measure the resistance between terminals 6 (CANH) and 16 (BAT), and between terminals 14 (CANL) and 16 (BAT) of the DLC3 each time a connector is disconnected.

Text in Illustration

Wiring Color

*1: 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/ Intuitive parking assist system

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

Result:

(d) When there is a short to +B in one or more of the bus lines that connect to an ECU (or sensor):

(1) Reconnect all of the connectors to the CAN junction connector, except for the one that was disconnected last (the bus line that is shorted to +B). Check that the resistance shown on the tester is normal (6 kOhms or more) to confirm that there is a short to +B in the one bus 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.

(e) When there is no short to +B in any of the bus lines that connect to the ECUs and sensors:

(1) With all the specified connectors for ECUs and sensors disconnected, proceed with the inspection of the CAN bus main lines between the CAN junction LH connector and CAN junction RH connector.

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

3. CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN J/C LH)

(a) Disconnect the CAN main bus line connector (I93) from the CAN junction LH 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.

Standard Resistance:

Text in Illustration

NG -- REPLACE CAN JUNCTION LH CONNECTOR
OK -- Continue to next step.

4. CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN J/C LH - CAN J/C RH)

(a) Reconnect the CAN main bus line connector (I93) to the CAN junction LH connector.

(b) Disconnect the CAN main bus line connector (I101) from the CAN junction RH connector.

Text in Illustration

Standard Resistance:

Text in Illustration

NG -- REPAIR OR REPLACE CAN MAIN BUS LINE (CAN J/C LH - CAN J/C RH)

OK -- REPLACE CAN JUNCTION RH CONNECTOR

5. CHECK FOR SHORT TO +B IN CAN BUS LINE (ECU, SENSOR)

(a) Reconnect the connector of the bus line that is shorted to +B to the CAN junction connector (the connector that caused the bus line resistance to change to 6 kOhms or more 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 bus line shorted to +B 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 changes to 6 kOhms or higher 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 BUS LINE OR CONNECTOR

OK -- REPLACE CORRESPONDING ECU OR SENSOR