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: w/ Navigation system (for DVD)
*2: w/ Navigation system (for HDD)
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
* After turning the power 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 notice before proceeding with work Service Precautions.
* Turn the power switch off before measuring the resistances between CAN main bus lines and between CAN branch lines.
* Turn the power switch off before inspecting CAN bus lines 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 +B IN CAN BUS LINE (CAN NO. 2 J/C)
(a) Disconnect the cable from the negative (-) battery terminal.
(b) Disconnect the wire harness connector from the CAN No. 2 junction connector rear side.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Result:
E -- CHECK FOR SHORT TO +B IN CONNECTED COMPONENT (ECU, SENSOR)
D -- CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 3 J/C)
C -- CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 1 J/C)
B -- REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO DLC3
A -- Continue to next step.
2. CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 2 J/C)
(a) Disconnect the wire harness connector from the CAN No. 2 junction connector front 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 +B IN CONNECTED COMPONENT (ECU, SENSOR)
A -- REPLACE CAN NO. 2 JUNCTION CONNECTOR
3. CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 1 J/C)
(a) Disconnect the instrument panel wire from the CAN No. 1 junction connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Result:
C -- CHECK FOR SHORT TO +B IN CONNECTED COMPONENT (ECU, SENSOR)
B -- REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 1 J/C - CAN NO. 2 J/C)
A -- Continue to next step.
4. CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 1 J/C)
(a) Disconnect the engine room main wire from the CAN No. 1 junction connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Result:
B -- CHECK FOR SHORT TO +B IN CONNECTED COMPONENT (ECU, SENSOR)
A -- REPLACE CAN NO. 1 JUNCTION CONNECTOR
5. CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 3 J/C)
(a) Disconnect the instrument panel wire from the CAN No. 3 junction connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Result:
C -- CHECK FOR SHORT TO +B IN CONNECTED COMPONENT (ECU, SENSOR)
B -- REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 2 J/C - CAN NO. 3 J/C)
A -- Continue to next step.
6. CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 3 J/C)
(a) Disconnect the engine room main wire from the CAN No. 3 junction connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Text in Illustration
Result:
B -- CHECK FOR SHORT TO +B IN CONNECTED COMPONENT (ECU, SENSOR)
A -- REPLACE CAN NO. 3 JUNCTION CONNECTOR
7. CHECK FOR SHORT TO +B IN CONNECTED COMPONENT (ECU, SENSOR)
(a) Reconnect all wire harness connectors (CAN J/C1, CAN J/C2 and CAN J/C3).
(b) Disconnect the ECU or sensor connected to the CAN bus line that is shorted to +B.
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 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/SENSOR WIRE OR CONNECTOR
OK -- REPLACE CORRESPONDING ECU OR SENSOR