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 the CAN bus main wire and GND when there is no resistance between terminals 6 (CANH) and 4 (CG) or 14 (CANL) and 4 (CG) of the DLC3.

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:
* Turn the power switch off before measuring the resistances between CAN bus main wires and between CAN bus branch wires.
* Turn the power switch off before inspecting CAN bus wires for a ground short.
* After the power 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 power 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 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 WIRE (CAN NO. 1 J/C)

(a) Turn the power switch off.

(b) Disconnect the wire harness connector from the CAN No. 1 junction connector upper side.

Text in Illustration

Result:

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

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

B -- CHECK FOR SHORT TO GND IN CAN BUS WIRE (CAN J/C LH)
A -- Continue to next step.

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

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

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 SHORT TO GND IN CAN BUS WIRE (CAN J/C RH)

A -- REPLACE CAN NO. 1 JUNCTION CONNECTOR

3. CHECK FOR SHORT TO GND IN CAN BUS WIRE (CAN J/C LH)

(a) Disconnect the instrument panel wire from the CAN junction connector LH.

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 -- REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 1 J/C - CAN J/C LH)
A -- Continue to next step.

4. CHECK SHORT TO GND IN CAN BUS WIRE (CAN J/C LH)

(a) Disconnect the engine room main wire from the CAN junction connector LH.

Text in Illustration

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

Standard Resistance:

Result:

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

A -- REPLACE CAN JUNCTION CONNECTOR LH

5. CHECK SHORT TO GND IN CAN BUS WIRE (CAN J/C RH)

(a) Disconnect the instrument panel wire from the CAN junction connector RH.

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 -- REPAIR CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 1 J/C - CAN J/C RH)
A -- Continue to next step.

6. CHECK SHORT TO GND IN CAN BUS WIRE (CAN J/C RH)

(a) Disconnect the engine room main wire from the CAN junction connector RH.

Text in Illustration

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

Standard Resistance:

Result:

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

A -- REPLACE CAN JUNCTION CONNECTOR RH

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

(a) Reconnect the CAN No. 1 junction connector to the CAN junction connector LH and RH wire harness connector.

(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 the terminals of ECU tables CAN Communication System.

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

Standard Resistance:

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).

Text in Illustration

NG -- REPAIR OR REPLACE CORRESPONDING ECU/SENSOR WIRE OR CONNECTOR

OK -- REPLACE CORRESPONDING ECU OR SENSOR