Check CAN Bus Line for Short to GND

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

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and GND when there is no resistance between terminals 6 (CANH) and 4 (CG) or 14 (CANL) and 4 (CG) of the DLC3.

*1: for Navigation receiver type

*2: for Radio and display type

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 system on using the cruise control switch (ON/OFF switch), wait at least 60 seconds, and then drive the vehicle at a speed of 50 km/h (31 mph) or more for at least 1.72 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.

PROCEDURE

1. CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN NO. 2 J/C)

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

(b) Disconnect the wire harness connector from the CAN No. 2 junction connector (instrument panel connector holder left side).

Text in Illustration

Result:

B -- CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN NO. 1 J/C)

C -- CHECK SHORT TO GND IN CAN BUS LINE (CAN NO. 3 J/C)

D -- CHECK FOR SHORT TO GND IN CONNECTED COMPONENT (ECU, SENSOR)
A -- Continue to next step.

2. CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN NO. 2 J/C)

(a) Disconnect the wire harness connector from the CAN No. 2 junction connector (instrument panel connector holder right side).

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

Standard Resistance:

*1: for Navigation receiver type

*2: for Radio and display type

Text in Illustration

*1: for Navigation receiver type

*2: for Radio and display type

Result:

B -- CHECK FOR SHORT TO GND IN CONNECTED COMPONENT (ECU, SENSOR)

C -- REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO DLC3

A -- REPLACE CAN NO. 2 JUNCTION CONNECTOR

3. CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN NO. 1 J/C)

(a) Disconnect the wire harness connector from the CAN No. 1 junction connector (instrument panel wire side).

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

Standard Resistance:

Text in Illustration

Result:

B -- REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 1 J/C - CAN NO. 2 J/C)

C -- CHECK FOR SHORT TO GND IN CONNECTED COMPONENT (ECU, SENSOR)
A -- Continue to next step.

4. CHECK SHORT TO GND IN CAN BUS LINE (CAN NO. 1 J/C)

(a) Disconnect the wire harness connector from the CAN No. 1 junction connector (engine room main wire side).

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

Standard Resistance:

Text in Illustration

Result:

B -- CHECK FOR SHORT TO GND IN CONNECTED COMPONENT (ECU, SENSOR)

A -- REPLACE CAN NO. 1 JUNCTION CONNECTOR

5. CHECK SHORT TO GND IN CAN BUS LINE (CAN NO. 3 J/C)

(a) Disconnect the wire harness connector from the CAN No. 3 junction connector (instrument panel wire side).

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

Standard Resistance:

Text in Illustration

Result:

B -- REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 2 J/C - CAN NO. 3 J/C)

C -- CHECK FOR SHORT TO GND IN CONNECTED COMPONENT (ECU, SENSOR)
A -- Continue to next step.

6. CHECK SHORT TO GND IN CAN BUS LINE (CAN NO. 3 J/C)

(a) Disconnect the wire harness connector from the CAN No. 3 junction connector (engine room main wire side).

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

Standard Resistance:

Text in Illustration

Result:

B -- CHECK FOR SHORT TO GND IN CONNECTED COMPONENT (ECU, SENSOR)

A -- REPLACE CAN NO. 3 JUNCTION CONNECTOR

7. CHECK FOR SHORT TO GND IN CONNECTED COMPONENT (ECU, SENSOR)

(a) Reconnect all wire harness connectors (CAN junction connector 1, CAN junction connector 2 and CAN junction connector 3).

(b) Disconnect the ECU or sensor connected to the CAN bus line that is shorted to ground.

HINT
If the ECU or sensor has multiple connectors, disconnect the connector that includes the CAN bus lines. To determine the ECU or sensor that is connected to the shorted bus line, refer to the terminals of ECU tables 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 200 Ohms 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/SENSOR WIRE OR CONNECTOR

OK -- REPLACE CORRESPONDING ECU OR SENSOR