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

A short to GND is suspected in the CAN bus when the resistance between terminals 4 (CG) and 6 (CANH), or terminals 4 (CG) and 14 (CANL) of the DLC3 is below 200 Ohms.

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:
* Turn the engine switch off before measuring the resistances between CAN bus main wires and between CAN bus branch wires.
* Turn the engine switch off before inspecting CAN bus wires for a ground short.
* After the engine switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.
* Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the engine switch, any other switches or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.

HINT
* Operating the engine 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 WIRE (DLC3 BRANCH WIRE)

(a) Turn the engine switch off.

(b) Disconnect the CAN No. 1 J/C wire harness connector.

Text in Illustration

Standard Resistance:

Text in Illustration

NG -- REPAIR OR REPLACE DLC3 BRANCH WIRE OR CONNECTOR
OK -- Continue to next step.

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

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

Standard Resistance:

Text in Illustration

Result:

C -- CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR)

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

A -- REPLACE CAN NO. 1 J/C

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

(a) Disconnect the CAN No. 2 J/C wire harness connector.

Text in Illustration

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

Standard Resistance:

Result:

C -- CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR)

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

A -- REPLACE CAN NO. 2 J/C

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

(a) Disconnect the CAN No. 3 J/C wire harness connector.

Text in Illustration

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

Standard Resistance:

Result:

D -- CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR)

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

B -- REPAIR OR REPLACE CAN BUS MAIN WIRE (CAN NO. 1 J/C - CAN NO. 3 J/C)

A -- REPLACE CAN NO. 3 J/C

5. CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR)

(a) Reconnect the CAN No. 1 J/C, CAN No. 2 J/C and CAN No. 3 J/C wire harness connectors.

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

HINT
If the ECU or sensor has multiple connectors, disconnect the connector that includes the CAN bus wires. To determine the ECU or sensor that is connected to the shorted bus wire, refer to 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 OR SENSOR BUS WIRE OR CONNECTOR

OK -- REPLACE CORRESPONDING ECU OR SENSOR